<SUBMISSION>
<ACCESSION-NUMBER>0000950123-06-013864
<TYPE>S-8
<PUBLIC-DOCUMENT-COUNT>4
<FILING-DATE>20061109
<DATE-OF-FILING-DATE-CHANGE>20061109
<EFFECTIVENESS-DATE>20061109
<FILER>
<COMPANY-DATA>
<CONFORMED-NAME>COMMVAULT SYSTEMS INC
<CIK>0001169561
<ASSIGNED-SIC>7372
<IRS-NUMBER>000000000
<STATE-OF-INCORPORATION>DE
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>S-8
<ACT>33
<FILE-NUMBER>333-138578
<FILM-NUMBER>061202810
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>2 CRESCENT PLACE
<CITY>OCEANPORT
<STATE>NJ
<ZIP>07757-0900
<PHONE>7328704000
</BUSINESS-ADDRESS>
</FILER>
<DOCUMENT>
<TYPE>S-8
<SEQUENCE>1
<FILENAME>y26896sv8.htm
<DESCRIPTION>ORIGINAL FILING ON FORM S-8
<TEXT>
<HTML>
<HEAD>
<TITLE>ORIGINAL FILING ON FORM S-8</TITLE>
</HEAD>
<BODY bgcolor="#FFFFFF">
<!-- PAGEBREAK -->
<H5 align="left" style="page-break-before:always"><A HREF="#toc">Table of Contents</A></H5><P>
<DIV style="font-family: 'Times New Roman',Times,serif">


<DIV align="center" style="font-size: 10pt; margin-top: 18pt">As filed with the Securities and Exchange Commission on November&nbsp;9, 2006
</DIV>


<DIV align="right" style="font-size: 10pt; margin-top: 12pt">File No.&nbsp;333-
</DIV>


<DIV style="width: 100%; border-bottom: 2pt solid black; font-size: 1pt">&nbsp;</DIV>
<DIV style="width: 100%; border-bottom: 1pt solid black; font-size: 1pt">&nbsp;</DIV>




<DIV align="center" style="font-size: 14pt; margin-top: 12pt"><B>UNITED STATES<BR>
SECURITIES AND EXCHANGE COMMISSION</B>
</DIV>

<DIV align="center" style="font-size: 12pt"><B>Washington, D.C. 20549</B>
</DIV>

<DIV align="center" style="font-size: 12pt"><B><DIV align="center"><DIV style="font-size: 3pt; margin-top: 16pt; width: 26%; border-top: 1px solid #000000">&nbsp;</DIV></DIV></B>
</DIV>

<DIV align="center" style="font-size: 18pt; margin-top: 12pt"><B>FORM S-8</B>
</DIV>


<DIV align="center" style="font-size: 12pt; margin-top: 12pt"><B>REGISTRATION STATEMENT UNDER THE<BR>
SECURITIES ACT OF 1933<BR>
<DIV align="center"><DIV style="font-size: 3pt; margin-top: 16pt; width: 26%; border-top: 1px solid #000000">&nbsp;</DIV></DIV></B>
</DIV>

<DIV align="center" style="font-size: 24pt; margin-top: 12pt"><B>COMMVAULT SYSTEMS, INC.</B>
</DIV>

<DIV align="center" style="font-size: 10pt">(Exact Name of Registrant as Specified in its Charter)</DIV>


<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="47%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="47%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD align="center" valign="top"><B>Delaware</B>
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top"><B>22-3447504</B></TD>
</TR>
<TR valign="bottom">
    <TD align="center" valign="top">(State or Other Jurisdiction
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">(I.R.S. Employer Identification No.)</TD>
</TR>
<TR valign="bottom">
    <TD align="center" valign="top">of Incorporation or Organization)</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD align="center" valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD align="center" valign="top"><B>2 Crescent Place</B></TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD align="center" valign="top"><B>Oceanport, New Jersey</B>
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top"><B>07757</B></TD>
</TR>
<TR valign="bottom">
    <TD align="center" valign="top">(Address of Principal Executive Offices)
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">(Zip Code)</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><DIV align="center"><DIV style="font-size: 3pt; margin-top: 16pt; width: 26%; border-top: 1px solid #000000">&nbsp;</DIV></DIV><BR>
<BR>
<B>1996 Stock Option Plan<BR>
2006 Long-Term Stock Incentive Plan</B><BR>
(Full Title of the Plan)<BR>
<BR>
<DIV align="center"><DIV style="font-size: 3pt; margin-top: 16pt; width: 26%; border-top: 1px solid #000000">&nbsp;</DIV></DIV>
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><B>N. Robert Hammer<BR>
Chairman, President and Chief Executive Officer<BR>
CommVault Systems, Inc.<BR>
2 Crescent Place<BR>
Oceanport, New Jersey 07757<BR>
(732)&nbsp;870-4000</B><BR>
(Name, Address and Phone Number of Agent For Service)<BR>
<BR>
<DIV align="center"><DIV style="font-size: 3pt; margin-top: 16pt; width: 26%; border-top: 1px solid #000000">&nbsp;</DIV></DIV><BR>
<B><I>Copy to:</I></B>
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><B>Philip J. Niehoff, Esq.<BR>
John R. Sagan, Esq.<BR>
Mayer, Brown, Rowe &#038; Maw LLP<BR>
71 South Wacker Drive<BR>
Chicago, Illinois 60606</B>
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><DIV align="center"><DIV style="font-size: 3pt; margin-top: 16pt; width: 26%; border-top: 1px solid #000000">&nbsp;</DIV></DIV>
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><B>CALCULATION OF REGISTRATION FEE</B>
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="1%">&nbsp;</TD>
    <TD width="34%">&nbsp;</TD>
    <TD width="2%">&nbsp;</TD><!-- VRule -->
    <TD width="2%">&nbsp;</TD>
    <TD width="12%">&nbsp;</TD>
    <TD width="2%">&nbsp;</TD><!-- VRule -->
    <TD width="2%">&nbsp;</TD>
    <TD width="12%">&nbsp;</TD>
    <TD width="2%">&nbsp;</TD><!-- VRule -->
    <TD width="2%">&nbsp;</TD>
    <TD width="12%">&nbsp;</TD>
    <TD width="2%">&nbsp;</TD><!-- VRule -->
    <TD width="2%">&nbsp;</TD>
    <TD width="12%">&nbsp;</TD>

    <TD width="1%">&nbsp;</TD>
</TR><TR style="font-size: 1px" valign="bottom">
    <TD nowrap align="left" colspan="15" style="border-bottom: 3px double #000000">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">    <TD width="1%">&nbsp;</TD>

    <TD>&nbsp;</TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Proposed</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Proposed</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">    <TD width="1%">&nbsp;</TD>

    <TD>&nbsp;</TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Maximum</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Maximum</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">    <TD width="1%">&nbsp;</TD>

    <TD nowrap align="center"><B>Title of Securities to be</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Amount to be</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Offering Price</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Aggregate</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Amount of</B></TD>
    <TD width="1%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">    <TD width="1%">&nbsp;</TD>

    <TD nowrap align="center"><B>Registered</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Registered(1)</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Per Share</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Offering Price</B></TD>
    <TD style="border-right: 2px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Registration Fee</B></TD>
    <TD width="1%">&nbsp;</TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD width="1%" style="border-top: 2px solid #000000">&nbsp;</TD>
                    <TD style="border-top: 2px solid #000000"><DIV style="margin-left:15px; text-indent:-15px">Common Stock, par value $0.01
per share</DIV></TD>
    <TD style="border-right: 2px solid #000000; border-top: 2px solid #000000">&nbsp;</TD>
    <TD style="border-top: 2px solid #000000">&nbsp;</TD>
    <TD align="center" valign="bottom" style="border-top: 2px solid #000000">4,000,000 (2)</TD>
    <TD style="border-right: 2px solid #000000; border-top: 2px solid #000000">&nbsp;</TD>
    <TD style="border-top: 2px solid #000000">&nbsp;</TD>
    <TD align="center" valign="bottom" style="border-top: 2px solid #000000">$18.95(3)</TD>
    <TD style="border-right: 2px solid #000000; border-top: 2px solid #000000">&nbsp;</TD>
    <TD style="border-top: 2px solid #000000">&nbsp;</TD>
    <TD align="center" valign="bottom" style="border-top: 2px solid #000000">$75,800,000(3)</TD>
    <TD style="border-right: 2px solid #000000; border-top: 2px solid #000000">&nbsp;</TD>
    <TD style="border-top: 2px solid #000000">&nbsp;</TD>
    <TD align="center" valign="bottom" style="border-top: 2px solid #000000">$8,110.60</TD>
    <TD width="1%" style="border-top: 2px solid #000000">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD width="1%" style="border-top: 2px solid #000000">&nbsp;</TD>
    <TD style="border-top: 2px solid #000000"><DIV style="margin-left:15px; text-indent:-15px">Common Stock, par value $0.01
per share</DIV></TD>
    <TD style="border-right: 2px solid #000000; border-top: 2px solid #000000">&nbsp;</TD>
    <TD style="border-top: 2px solid #000000">&nbsp;</TD>
    <TD align="center" valign="bottom" style="border-top: 2px solid #000000">7,921,426 (4)</TD>
    <TD style="border-right: 2px solid #000000; border-top: 2px solid #000000">&nbsp;</TD>
    <TD style="border-top: 2px solid #000000">&nbsp;</TD>
    <TD align="center" valign="bottom" style="border-top: 2px solid #000000">$6.08(5)</TD>
    <TD style="border-right: 2px solid #000000; border-top: 2px solid #000000">&nbsp;</TD>
    <TD style="border-top: 2px solid #000000">&nbsp;</TD>
    <TD align="center" valign="bottom" style="border-top: 2px solid #000000">$48,162,270(5)</TD>
    <TD style="border-right: 2px solid #000000; border-top: 2px solid #000000">&nbsp;</TD>
    <TD style="border-top: 2px solid #000000">&nbsp;</TD>
    <TD align="center" valign="bottom" style="border-top: 2px solid #000000">$5,153.36</TD>
    <TD width="1%" style="border-top: 2px solid #000000">&nbsp;</TD>
</TR>
<TR style="font-size: 1px" valign="bottom">
    <TD nowrap align="left" colspan="15" style="border-top: 3px double #000000">&nbsp;</TD>
</TR>

<!-- End Table Body -->
</TABLE>
</DIV>

<DIV style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top" style="font-size: 9pt; color: #000000; background: transparent">
    <TD width="3%" nowrap align="left">(1)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>In accordance with Rule 416(a) under the Securities Act of 1933, as amended, this registration statement
shall be deemed to cover any additional shares of the Registrant&#146;s Common Stock, which may be issued
pursuant to the employee benefit plans described herein to prevent dilution from stock splits, stock
dividends or similar transactions.</TD>
</TR>

<TR>
    <TD style="font-size: 6pt">&nbsp;</TD>
</TR><TR valign="top" style="font-size: 9pt; color: #000000; background: transparent">
    <TD width="3%" nowrap align="left">(2)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>Shares available for grant, but not yet granted as of the date of this
registration statement under the employee benefit plans described
herein.</TD>
</TR>

<TR>
    <TD style="font-size: 6pt">&nbsp;</TD>
</TR><TR valign="top" style="font-size: 9pt; color: #000000; background: transparent">
    <TD width="3%" nowrap align="left">(3)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>Estimated solely for the purpose of calculating the registration fee
pursuant to Rule 457(c) and Rule 457(h) under the Securities Act of
1933, as amended, and based upon the average of the high and low prices
of the Registrant&#146;s Common Stock as reported on the Nasdaq Global
Market on November&nbsp;6, 2006.</TD>
</TR>

<TR>
    <TD style="font-size: 6pt">&nbsp;</TD>
</TR><TR valign="top" style="font-size: 9pt; color: #000000; background: transparent">
    <TD width="3%" nowrap align="left">(4)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>Shares subject to options outstanding under the employee benefit plans
described herein as of the date of this registration statement.</TD>
</TR>

<TR>
    <TD style="font-size: 6pt">&nbsp;</TD>
</TR><TR valign="top" style="font-size: 9pt; color: #000000; background: transparent">
    <TD width="3%" nowrap align="left">(5)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>Estimated solely for the purpose of calculating the registration fee
pursuant to Rule 457(h) under the Securities Act of 1933, as amended,
and based upon the weighted average exercise price (rounded to the
nearest cent) for such outstanding options.</TD>
</TR>

</TABLE>
</DIV>

<DIV style="width: 100%; border-bottom: 1pt solid black; margin-top: 10pt; font-size: 1pt">&nbsp;</DIV>
<DIV style="width: 100%; border-bottom: 2pt solid black; font-size: 1pt">&nbsp;</DIV>





<P align="center" style="font-size: 10pt">&nbsp;
</DIV>

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<P><HR noshade><P>

<DIV style="font-family: 'Times New Roman',Times,serif">

<!-- TOC -->
<A name="toc"><DIV align="CENTER" style="page-break-before:always"><U><B>TABLE OF CONTENTS</B></U></DIV></A>

<P><CENTER>
<TABLE border="0" width="90%" cellpadding="0" cellspacing="0">
<TR>
	<TD width="3%"></TD>
	<TD width="3%"></TD>
	<TD width="3%"></TD>
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	<TD width="3%"></TD>
	<TD width="3%"></TD>
	<TD width="3%"></TD>
	<TD width="3%"></TD>
	<TD width="76%"></TD>
</TR>
<TR><TD colspan="9"><A HREF="#000">PART II</A></TD></TR>
<TR><TD></TD><TD colspan="8"><A HREF="#001">Item&nbsp;3. Incorporation of Documents by Reference.</A></TD></TR>
<TR><TD></TD><TD colspan="8"><A HREF="#002">Item&nbsp;4. Description of Securities.</A></TD></TR>
<TR><TD></TD><TD colspan="8"><A HREF="#003">Item&nbsp;5. Interests of Named Experts and Counsel.</A></TD></TR>
<TR><TD></TD><TD colspan="8"><A HREF="#004">Item&nbsp;6. Indemnification of Directors and Officers.</A></TD></TR>
<TR><TD></TD><TD colspan="8"><A HREF="#005">Item&nbsp;7. Exemption from Registration Claimed.</A></TD></TR>
<TR><TD></TD><TD colspan="8"><A HREF="#006">Item&nbsp;8. Exhibits.</A></TD></TR>
<TR><TD></TD><TD colspan="8"><A HREF="#007">Item&nbsp;9. Undertakings.</A></TD></TR>
<TR><TD colspan="9"><A HREF="#008">SIGNATURES</A></TD></TR>
<TR><TD colspan="9"><A HREF="#009">POWER OF ATTORNEY</A></TD></TR>
<TR><TD colspan="9"><A HREF="#010">EXHIBIT INDEX</A></TD></TR>
<TR><TD colspan="9"><A HREF="y26896exv5w1.htm">EX-5.1: OPINION OF MAYER, BROWN, ROWE & MAW LLP</A></TD></TR>
<TR><TD colspan="9"><A HREF="y26896exv23w1.htm">EX-23.1: CONSENT OF ERNST & YOUNG LLP</A></TD></TR>
</TABLE>
</CENTER>
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<H5 align="left" style="page-break-before:always"><A HREF="#toc">Table of Contents</A></H5><P>




<!-- link1 "PART II" -->
<DIV align="left"><A NAME="000"></A></DIV>

<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><B>PART II</B>
</DIV>

<DIV align="center" style="font-size: 10pt"><B>INFORMATION REQUIRED IN THE REGISTRATION STATEMENT</B></DIV>


<!-- link2 "Item&nbsp;3. Incorporation of Documents by Reference." -->
<DIV align="left"><A NAME="001"></A></DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;3. Incorporation of Documents by Reference.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The following documents filed by CommVault Systems, Inc., a Delaware corporation (the
&#147;Company&#148;), with the Securities and Exchange Commission (the &#147;Commission&#148;) are incorporated by
reference in this Registration Statement:
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt; margin-left: 3%">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a)&nbsp;The
 Company&#146;s Prospectus filed pursuant to Rule 424(b) under the Securities Act of
1933, as amended (the &#147;Securities Act&#148;) relating to the Company&#146;s Registration Statement on
Form S-1, as amended (Registration No.&nbsp;333-132550); and
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt; margin-left: 3%">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b)&nbsp;The description of the Company&#146;s common stock, par value $0.01 per share, contained
in the Company&#146;s Registration Statement on Form 8-A/A filed with the Commission on September
19, 2006 pursuant to Section 12(b) of the Securities Exchange Act of 1934, as amended (the
&#147;Exchange Act&#148;), including any subsequent amendment or any report filed for the purpose of
updating such description.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;All documents filed by the Company pursuant to Section&nbsp;13(a), 13(c), 14, or 15(d) of the
Exchange Act, prior to the filing of a post-effective amendment which indicates that all securities
offered have been sold or which deregisters all securities then remaining unsold, shall be deemed
to be incorporated by reference herein and to be a part hereof from the date of filing of such
documents. Any statement contained herein or in a document incorporated or deemed to be
incorporated by reference herein shall be deemed to be modified or superseded for purposes of this
Registration Statement to the extent that a statement contained herein or in any subsequently filed
document which also is or is deemed to be incorporated by reference herein modifies or supersedes
such statement. Any such statement so modified or superseded shall not be deemed, except as so
modified or superseded, to constitute a part of this Registration Statement.
</DIV>
<!-- link2 "Item&nbsp;4. Description of Securities." -->
<DIV align="left"><A NAME="002"></A></DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;4. Description of Securities.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Not applicable.
</DIV>

<!-- link2 "Item&nbsp;5. Interests of Named Experts and Counsel." -->
<DIV align="left"><A NAME="003"></A></DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;5. Interests of Named Experts and Counsel.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Not applicable.
</DIV>

<!-- link2 "Item&nbsp;6. Indemnification of Directors and Officers." -->
<DIV align="left"><A NAME="004"></A></DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;6. Indemnification of Directors and Officers.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Section&nbsp;102 of the Delaware General Corporation Law (&#147;DGCL&#148;), as amended, allows a corporation
to eliminate the personal liability of directors of a corporation to the corporation or its
stockholders for monetary damages for a breach of fiduciary duty as a director, except where the
director breached his duty of loyalty, failed to act in good faith, engaged in intentional
misconduct or knowingly violated a law, authorized the payment of a dividend or approved a stock
repurchase in violation of Delaware law or obtained an improper personal benefit.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Section&nbsp;145 of the DGCL provides, among other things, that a corporation may indemnify any
person who was or is a party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding (other than an action by or in the right of the corporation)
by reason of the fact that the person is or was a director, officer, agents or employee of the
corporation or is or was serving at the corporation&#146;s request as a director, officer, agent or
employee of another corporation, partnership, joint venture, trust or other enterprise, against
expenses, including attorneys&#146; fees, judgments, fines and amounts paid in settlement actually and
reasonably incurred by the person in connection with such action, suit or proceeding. The power to
indemnify applies (a)&nbsp;if such person is successful on the merits or otherwise in defense of any
action, suit or proceeding or (b)&nbsp;if such person acted in good faith and in a manner he reasonably
believed to be in the best interests, or not opposed to the best interests, of the corporation, and
with respect to any criminal action or proceeding, had no reasonable cause to believe his conduct
was unlawful. The power to indemnify applies to actions brought by or in the right of the
corporation as well, but only to the extent of expenses (including attorneys&#146; fees but excluding
amounts paid in settlement) actually and reasonably incurred in the defense or settlement of such
action and not to any satisfaction of judgment or settlement of the claim itself, and with the
further limitation that in such actions no indemnification
</DIV>

<P align="center" style="font-size: 10pt">&nbsp;
</DIV>

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<H5 align="left" style="page-break-before:always"><A HREF="#toc">Table of Contents</A></H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">
<DIV align="left" style="font-size: 10pt; margin-top: 6pt">shall be made in the event of any adjudication of negligence or misconduct in the performance of
duties to the corporation, unless the court believes that in light of all the circumstances
indemnification should apply.
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Section&nbsp;174 of the DGCL provides, among other things, that a director, who willfully or
negligently approves of an unlawful payment of dividends or an unlawful stock purchase or
redemption, shall be held liable for such actions. A director who was either absent when the
unlawful actions were approved or dissented at the time, may avoid liability by causing his or her
dissent to such actions to be entered on the books containing the minutes of the meetings of the
board of directors at the time such actions occurred or immediately after such absent director
receives notice of the unlawful acts.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The Company&#146;s certificate of incorporation provides that, pursuant to Delaware law, its
directors shall not be liable for monetary damages for breach of the directors&#146; fiduciary duty of
care to the Company and its stockholders. This provision in the certificate of incorporation does
not eliminate the duty of care, and in appropriate circumstances equitable remedies such as
injunctive or other forms of non-monetary relief will remain available under Delaware law. In
addition, each director will continue to be subject to liability for breach of the director&#146;s duty
of loyalty to the Company or its stockholders, for acts or omissions not in good faith or involving
intentional misconduct or knowing violations of law, for actions leading to improper personal
benefit to the director and for payment of dividends or approval of stock repurchases or
redemptions that are unlawful under Delaware law. The provision also does not affect a director&#146;s
responsibilities under any other law, such as the federal securities laws or state or federal
environmental laws.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The Company&#146;s bylaws provide that it must indemnify its directors and officers to the fullest
extent permitted by Delaware law and require the Company to advance litigation expenses upon its
receipt of an undertaking by or on behalf of a director or officer to repay such advances if it is
ultimately determined that such director or officer is not entitled to indemnification. The
indemnification provisions contained in the Company&#146;s bylaws are not exclusive of any other rights
to which a person may be entitled by law, agreement, vote of stockholders or disinterested
directors or otherwise. The Company has obtained directors&#146; and officers&#146; liability insurance.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;In addition, the Company has entered into agreements to indemnify its directors and certain of
its officers in addition to the indemnification provided for in the certificate of incorporation
and bylaws. These agreements, among other things, indemnify the Company&#146;s directors and some of its
officers for certain expenses (including attorneys&#146; fees), judgments, fines and settlement amounts
incurred by such person in any action or proceeding, including any action by or in the Company&#146;s
right, on account of services by that person as a director or officer of the Company or as a
director or officer of any of the Company&#146;s subsidiaries, or as a director or officer of any other
company or enterprise that the person provides services to at the Company&#146;s request.
</DIV>
<!-- link2 "Item&nbsp;7. Exemption from Registration Claimed." -->
<DIV align="left"><A NAME="005"></A></DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;7. Exemption from Registration Claimed.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Not applicable.
</DIV>

<!-- link2 "Item&nbsp;8. Exhibits." -->
<DIV align="left"><A NAME="006"></A></DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;8. Exhibits.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;See Index to Exhibits, which is incorporated herein by reference.
</DIV>

<!-- link2 "Item&nbsp;9. Undertakings." -->
<DIV align="left"><A NAME="007"></A></DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;9. Undertakings.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a)&nbsp;The undersigned registrant hereby undertakes:
</DIV>


<DIV style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="6%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">(1)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>To file, during any period in which offers or sales are being
made, a post-effective amendment to this registration statement:</TD>
</TR>

</TABLE>
</DIV>

<DIV style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="10%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">(i)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>To include any prospectus required by Section&nbsp;10(a)(3)
of the Securities Act of 1933;</TD>
</TR>

</TABLE>
</DIV>

<DIV style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="10%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">(ii)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>To reflect in the prospectus any facts or events
arising after the effective date of this registration statement (or the
most recent post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth in
this registration statement. Notwithstanding the foregoing, any increase or
decrease in volume of securities offered (if the total dollar volume of
securities offered would not exceed that which was registered) and any
deviation from the low or high end of the estimated maximum offering range
may be reflected in the form of prospectus filed with the Commission
pursuant to Rule 424(b) if, in the aggregate, the changes in volume</TD>
</TR>

</TABLE>
</DIV>

<P align="center" style="font-size: 10pt">&nbsp;
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always"><A HREF="#toc">Table of Contents</A></H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">

<DIV style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="10%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>and price represent no more than 20% change in the maximum aggregate
offering price set forth in the &#147;Calculation of Registration Fee&#148; table in
the effective Registration Statement;</TD>
</TR>

<TR>
    <TD style="font-size: 6pt">&nbsp;</TD>
</TR><TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="10%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">(iii)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>To include any material information with respect to
the plan of distribution not previously disclosed in this registration
statement or any material change to such information in this registration
statement;</TD>
</TR>

</TABLE>
</DIV>

<DIV style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="6%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if
the information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed with or furnished to the
Commission by the registrant pursuant to Section&nbsp;13 or 15(d) of the Securities
Exchange Act of 1934 that are incorporated by reference in this registration
statement.</TD>
</TR>

<TR>
    <TD style="font-size: 6pt">&nbsp;</TD>
</TR><TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="6%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">(2)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to
be a new registration statement relating to the securities offered therein, and
the offering of such securities at that time shall be deemed to be the initial
bona fide offering thereof.</TD>
</TR>

<TR>
    <TD style="font-size: 6pt">&nbsp;</TD>
</TR><TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="6%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">(3)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>To remove from registration by means of a post-effective
amendment any of the securities being registered which remain unsold at the
termination of the offering.</TD>
</TR>

</TABLE>
</DIV>

<DIV style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="2%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">(b)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>The undersigned registrant hereby undertakes that, for purposes of determining
any liability under the Securities Act of 1933, each filing of the registrant&#146;s annual
report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (and,
where applicable, each filing of an employee benefit plan&#146;s annual report pursuant to
Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference
in this registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities at that
time shall be deemed to be the initial bona fide offering thereof.</TD>
</TR>

</TABLE>
</DIV>

<DIV style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="2%" style="background: transparent">&nbsp;</TD>
    <TD width="3%" nowrap align="left">(c)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>Insofar as indemnification for liabilities arising under the Securities Act of
1933 may be permitted to directors, officers and controlling persons of the registrant
pursuant to the provisions of the registrant&#146;s articles of incorporation, by-laws or
otherwise, the registrant has been advised that in the opinion of the Commission such
indemnification is against public policy as expressed in the Securities Act of 1933 and
is, therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the registrant of expenses incurred or paid
by a director, officer or controlling person of the registrant in the successful
defense of any action, suit or proceeding) is asserted by such director, officer or
controlling person in connection with the securities being registered, the registrant
will, unless in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Securities Act of
1933 and will be governed by the final adjudication of such issue.</TD>
</TR>

</TABLE>
</DIV>

<P align="center" style="font-size: 10pt">&nbsp;
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always"><A HREF="#toc">Table of Contents</A></H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">
<!-- link1 "SIGNATURES" -->
<DIV align="left"><A NAME="008"></A></DIV>

<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><B>SIGNATURES</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it
has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and
has duly caused this registration statement to be signed on its behalf by the undersigned,
thereunto duly authorized, in the City of Oceanport, State of New Jersey, on November&nbsp;9, 2006.
</DIV>

<TABLE width="100%" border="0" cellspacing="0" cellpadding="0" style="font-size: 10pt">
<TR>
    <TD width="48%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="40%">&nbsp;</TD>
    <TD width="10%">&nbsp;</TD>
</TR>
<TR>
    <TD valign="top" align="left">&nbsp;</TD>
    <TD colspan="3" align="left"><B>COMMVAULT SYSTEMS, INC.</B><BR>
&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR><TR>
    <TD align="left">&nbsp;</TD>
    <TD valign="top">By:&nbsp;&nbsp;</TD>
    <TD colspan="2" style="border-bottom: 1px solid #000000" align="center">/s/    N. ROBERT HAMMER
&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR><TR>
    <TD align="left">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD colspan="2" align="center">N. Robert Hammer&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR><TR>
    <TD align="left">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD colspan="2" align="center"><I>Chairman, President and Chief Executive Officer</I>&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR>
<TR>
    <TD colspan="5">&nbsp;</TD>
</TR>
</TABLE>
<!-- link1 "POWER OF ATTORNEY" -->
<DIV align="left"><A NAME="009"></A></DIV>

<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><B>POWER OF ATTORNEY</B>
</DIV>



<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes
and appoints, jointly and severally, N. Robert Hammer, Louis F. Miceli and Warren H. Mondschein his
or her attorneys-in-fact, each with the power of substitution, for him in any and all capacities,
to sign any amendments to this Registration Statement on Form S-8 (including post-effective
amendments), and to file the same, with all exhibits thereto, and other documents in connection
therewith, with the Commission, hereby ratifying and confirming all that each of said
attorneys-in-fact, or his or her substitute or substitutes, may do or cause to be done by virtue
hereof.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pursuant to the requirements of the Securities Act of 1933, this registration statement has
been signed by the following persons in the capacities indicated on November&nbsp;9, 2006.
</DIV>
<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="45%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="45%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="center"><U><B>Name</B></u></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B><u>Title</u></B></TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom"><!-- Blank Space -->
    <TD align="right">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/     N. ROBERT HAMMER
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
N. Robert Hammer</TD>
    <TD>&nbsp;</TD>
    <TD valign="top" align="center">
Chairman, President and Chief Executive Officer</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/     LOUIS F. MICELI
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
Louis F. Miceli</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">
Vice President, Chief Financial Officer</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/    BRIAN CAROLAN
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
Brian Carolan</TD>
    <TD>&nbsp;</TD>
        <TD align="center" valign="top">
Vice President, Finance and Chief Accounting Officer</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/    THOMAS BARRY
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
Thomas Barry</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">
Director</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/    FRANK J. FANZILLI, JR.
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
Frank J. Fanzilli, Jr.</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">
Director</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/    ARMANDO GEDAY
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
Armando Geday</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">
Director</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/    KEITH GEESLIN
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
Keith Geeslin</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">
Director</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/    F. ROBERT KURIMSKY
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
F. Robert Kurimsky</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">
Director</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>


<P align="center" style="font-size: 10pt">&nbsp;
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always"><A HREF="#toc">Table of Contents</A></H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">
<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="45%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="45%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="center"><U><B>Name</B></u></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B><u>Title</u></B></TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom"><!-- Blank Space -->
    <TD align="right">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
Daniel Pulver</TD>
    <TD>&nbsp;</TD>
       <TD align="center" valign="top">
Director</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/    GARY SMITH
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
Gary Smith</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">
Director</TD>
</TR>
<TR valign="bottom" style="padding-top: 1em">
    <TD align="center" valign="top">/s/     DAVID F. WALKER
<DIV style="font-size: 1pt; border-bottom: 1px solid #000000">&nbsp;</DIV>
David F. Walker</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">
Director</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>


<P align="center" style="font-size: 10pt">&nbsp;
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always"><A HREF="#toc">Table of Contents</A></H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">
<!-- link1 "EXHIBIT INDEX" -->
<DIV align="left"><A NAME="010"></A></DIV>

<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><B>EXHIBIT INDEX</B>
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="7%">&nbsp;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="90%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left"><B>Exhibit</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left"><B><u>Numbers</u></B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B><U>Description</u></B></TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">4.1
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Form of Common Stock Certificate (incorporated by reference to
Exhibit&nbsp;4.1 to the
Registrant&#146;s Registration
Statement on Form&nbsp;S-1, File
No.&nbsp;333-132550)</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">4.2
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Amended and Restated Certificate of Incorporation of CommVault Systems, Inc.
(incorporated by reference to Exhibit&nbsp;3.2 to the Registrant&#146;s Registration Statement on Form
S-1, File No.&nbsp;333-132550)</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">4.3
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Amended and Restated Bylaws of CommVault Systems, Inc. (incorporated by reference to
Exhibit&nbsp;3.3 to the Registrant&#146;s Registration Statement on Form&nbsp;S-1, File No.&nbsp;333-132550)</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">4.4
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">CommVault Systems, Inc. 1996 Stock Option Plan, as amended (incorporated by reference to
Exhibit&nbsp;10.2 to the Registrant&#146;s Registration Statement on Form&nbsp;S-1, File No.&nbsp;333-132550)</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">4.5
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">CommVault Systems, Inc. 2006 Long-Term Stock Incentive Plan (incorporated by reference to
Exhibit&nbsp;10.3 to the Registrant&#146;s Registration Statement on Form&nbsp;S-1, File No.&nbsp;333-132550)</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">5.1
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Opinion of Mayer, Brown, Rowe &#038; Maw LLP</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">23.1
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Consent of Ernst &#038; Young LLP</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">23.2
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Consent of Mayer, Brown, Rowe &#038; Maw LLP (included in Exhibit&nbsp;5.1)</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">24.1
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Power of Attorney (included on signature page hereto)</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>



<P align="center" style="font-size: 10pt">&nbsp;
</DIV>


</BODY>
</HTML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-5.1
<SEQUENCE>2
<FILENAME>y26896exv5w1.htm
<DESCRIPTION>EX-5.1: OPINION OF MAYER, BROWN, ROWE & MAW LLP
<TEXT>
<HTML>
<HEAD>
<TITLE>EX-5.1</TITLE>
</HEAD>
<BODY bgcolor="#FFFFFF">
<!-- PAGEBREAK -->
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>
<DIV style="font-family: 'Times New Roman',Times,serif">


<DIV align="right" style="font-size: 10pt; margin-top: 12pt">Exhibit&nbsp;5.1
</DIV>


<DIV align="right" style="font-size: 10pt; margin-top: 12pt"><IMG src="y26896y2689601.gif" alt="(MAYER, BROWN, ROWE &#038; MAW COMPANY LOGO)">
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="45%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="50%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">November&nbsp;9, 2006
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="right" valign="top"><FONT style="font-size:8pt">Mayer,
Brown, Rowe &#038; Maw LLP</FONT></TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="right" valign="top"><FONT style="font-size:8pt">71 South Wacker Drive</FONT></TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="right" valign="top"><FONT style="font-size:8pt">Chicago, Illinois 60606-4637</FONT></TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="45%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="50%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">CommVault Systems, Inc.
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="right" valign="top"><FONT style="font-size:8pt">Main Tel (312)&nbsp;782-0600</FONT></TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">2 Crescent Place
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="right" valign="top"><FONT style="font-size:8pt">Main Fax (312)&nbsp;701-7711</FONT></TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Oceanport, New Jersey 07757
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="right" valign="top"><FONT style="font-size:8pt">www.mayerbrownrowe.com</FONT></TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 12pt">Ladies and Gentlemen:
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;We are acting as special
 counsel to CommVault Systems, Inc. (the &#147;Company&#148;) in connection with
the registration under the Securities Act of 1933, as amended, of 7,921,426 shares of its Common
Stock, $0.01 par value per share (&#147;Common Stock&#148;) to be offered pursuant to the Company&#146;s 1996
Stock Option Plan and 4,000,000 shares of its Common Stock to be
 offered pursuant to the Company&#146;s
2006 Long-Term Stock Incentive Plan (together the 1996 Stock Option Plan and the 2006 Long-Term Stock Incentive
Plan are referred to herein as the &#147;Plans&#148;). In connection therewith, we have examined or are
otherwise familiar with the Company&#146;s Amended and Restated Certificate of Incorporation, the
Company&#146;s Amended and Restated By-Laws, the Plans, the Company&#146;s Registration Statement on Form S-8
(the &#147;Registration Statement&#148;) relating to the shares of Common Stock, relevant resolutions of the
Board of Directors of the Company, and such other documents and instruments as we have deemed
necessary for the purposes of rendering this opinion.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Based upon the foregoing, we are of the opinion that the shares of Common Stock registered on
the Registration Statement are duly authorized for issuance and when issued in accordance with the
provisions of the Plans will be validly issued, fully paid and non-assessable shares of the
Company.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;We hereby consent to the filing of this opinion as an exhibit to the Registration Statement.
</DIV>

<TABLE width="100%" border="0" cellspacing="0" cellpadding="0" style="font-size: 10pt">
<TR>
    <TD width="48%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="35%">&nbsp;</TD>
    <TD width="15%">&nbsp;</TD>
</TR>
<TR>
    <TD valign="top" align="left">&nbsp;</TD>
    <TD colspan="3" align="left">Very truly yours,<BR>
&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR><TR>
    <TD align="left">&nbsp;</TD>
    <TD colspan="3" align="left">/s/ Mayer, Brown, Rowe &#038; Maw LLP
&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR><TR>
    <TD align="left">&nbsp;</TD>
    <TD colspan="3" align="left">&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR><TR>
    <TD align="left">&nbsp;</TD>
    <TD colspan="3" align="left"><B>MAYER, BROWN, ROWE &#038; MAW LLP</B>&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR>
<TR>
    <TD colspan="5">&nbsp;</TD>
</TR>
</TABLE>

<DIV align="center" style="font-size: 7pt; margin-top: 18pt">Berlin&nbsp;&nbsp;&nbsp;Brussels&nbsp;&nbsp;&nbsp;Charlotte&nbsp;&nbsp;&nbsp;Chicago&nbsp;&nbsp;&nbsp;Cologne&nbsp;&nbsp;&nbsp;Frankfurt&nbsp;&nbsp;&nbsp;Houston&nbsp;&nbsp;&nbsp;London&nbsp;&nbsp;&nbsp;Los Angeles&nbsp;&nbsp;&nbsp;New York&nbsp;&nbsp;&nbsp;Palo Alto&nbsp;&nbsp;&nbsp;Paris&nbsp;&nbsp;&nbsp;Washington, D.C.<BR>
Independent Mexico City Correspondent: Jauregui, Navarrete y Nader S.C.
</DIV>


<DIV align="center" style="font-size: 7pt; margin-top: 18pt">Mayer, Brown, Rowe &#038; Maw LLP operates in combination with our associated English limited liability partnership in the offices listed above.
</DIV>



<P align="center" style="font-size: 10pt">
</DIV>

</BODY>
</HTML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-23.1
<SEQUENCE>3
<FILENAME>y26896exv23w1.htm
<DESCRIPTION>EX-23.1: CONSENT OF ERNST & YOUNG LLP
<TEXT>
<HTML>
<HEAD>
<TITLE>EX-23.1</TITLE>
</HEAD>
<BODY bgcolor="#FFFFFF">
<!-- PAGEBREAK -->
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>
<DIV style="font-family: 'Times New Roman',Times,serif">


<DIV align="right" style="font-size: 10pt; margin-top: 12pt">Exhibit&nbsp;23.1
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 18pt">Consent of Independent Registered Public Accounting Firm
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">We consent to the incorporation by reference in the Registration Statement (Form S-8 No.&nbsp;333-00000)
pertaining to the 1996 Stock Option Plan and the 2006 Long-Term Stock Incentive Plan of CommVault
Systems, Inc. of our report dated June&nbsp;28, 2006 with respect to the consolidated financial
statements and schedule of CommVault Systems, Inc. included in its Registration Statement (Form&nbsp;S-1
No.&nbsp;333-132550) of CommVault Systems Inc. filed with the Securities and Exchange Commission.
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 18pt; margin-left:60%">/s/ Ernst &#038; Young LLP</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">MetroPark, New Jersey<BR>
November&nbsp;7, 2006

</DIV>


<P align="center" style="font-size: 10pt">
</DIV>

</BODY>
</HTML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>4
<FILENAME>y26896y2689601.gif
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