<SEC-DOCUMENT>0000709283-21-000048.txt : 20210817
<SEC-HEADER>0000709283-21-000048.hdr.sgml : 20210817
<ACCEPTANCE-DATETIME>20210817121424
ACCESSION NUMBER:		0000709283-21-000048
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210812
FILED AS OF DATE:		20210817
DATE AS OF CHANGE:		20210817

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FICHTHORN JOHN
		CENTRAL INDEX KEY:			0001411509

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13449
		FILM NUMBER:		211181924

	MAIL ADDRESS:	
		STREET 1:		C/O DIALECTIC CAPITAL MANAGEMENT, LLC
		STREET 2:		17 STATE STREET, SUITE 3930
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10004

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			QUANTUM CORP /DE/
		CENTRAL INDEX KEY:			0000709283
		STANDARD INDUSTRIAL CLASSIFICATION:	COMPUTER STORAGE DEVICES [3572]
		IRS NUMBER:				942665054
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		224 AIRPORT PARKWAY
		STREET 2:		SUITE 550
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110
		BUSINESS PHONE:		408 944 4000

	MAIL ADDRESS:	
		STREET 1:		224 AIRPORT PARKWAY
		STREET 2:		SUITE 550
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>wf-form4a_162921685038853.xml
<DESCRIPTION>FORM 4/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2021-08-12</periodOfReport>

    <dateOfOriginalSubmission>2021-08-16</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000709283</issuerCik>
        <issuerName>QUANTUM CORP /DE/</issuerName>
        <issuerTradingSymbol>QMCO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001411509</rptOwnerCik>
            <rptOwnerName>FICHTHORN JOHN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O QUANTUM CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>224 AIRPORT PARKWAY, SUITE 550</rptOwnerStreet2>
            <rptOwnerCity>SAN JOSE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95110</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-08-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.7295</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>154740</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <remarks>The purpose of this amendment is solely to correct an administrative error relating to the transaction date in Table I, Box 2 of the Reporting Person's Form 4. This corrected Form 4 reflects the correct date of August 12, 2021 in Table 1, Box 2 (Transaction Date).</remarks>

    <ownerSignature>
        <signatureName>/s/ Josie Buensuceso, as Attorney-In-Fact</signatureName>
        <signatureDate>2021-08-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
