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  <xs:element id="hrth_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageRemainingContractualTerm" abstract="false" name="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageRemainingContractualTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="hrth_DeferredTaxAssetsLeasesLiability" abstract="false" name="DeferredTaxAssetsLeasesLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_LeaseLiabilityNoncurrent" abstract="false" name="LeaseLiabilityNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_DefinedBenefitPlanExpectedFutureBenefitPayments" abstract="false" name="DefinedBenefitPlanExpectedFutureBenefitPayments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumberAdjustmentAndCorrection" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumberAdjustmentAndCorrection" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="hrth_TwentyFiveCustomersMember" abstract="true" name="TwentyFiveCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_NumberOfFacilities" abstract="false" name="NumberOfFacilities" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="hrth_EquityIncentivePlan2020Member" abstract="true" name="EquityIncentivePlan2020Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_LeaseImpairmentAndTerminationChargesMember" abstract="true" name="LeaseImpairmentAndTerminationChargesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_FacilityAssetImpairmentAndOtherExpenseMember" abstract="true" name="FacilityAssetImpairmentAndOtherExpenseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_LesseeLeasesSupplementalBalanceSheetInformationTableTextBlock" abstract="false" name="LesseeLeasesSupplementalBalanceSheetInformationTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="hrth_EffectiveIncomeTaxRateReconciliationAdjustmentsToStateAttributes" abstract="false" name="EffectiveIncomeTaxRateReconciliationAdjustmentsToStateAttributes" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_RelatedPartyTransactionsPolicyPolicyTextBlock" abstract="false" name="RelatedPartyTransactionsPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="hrth_CashEquivalentMember" abstract="true" name="CashEquivalentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_LeaseLiabilityCurrent" abstract="false" name="LeaseLiabilityCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_DeferredCompensationAndRetirementPlan" abstract="false" name="DeferredCompensationAndRetirementPlan" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_CustomerCareMember" abstract="true" name="CustomerCareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_TexasCapitalBankMember" abstract="true" name="TexasCapitalBankMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_LesseeLeaseRenewalTerm" abstract="false" name="LesseeLeaseRenewalTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="hrth_LeasesWeightedAverageDiscountRateAbstract" abstract="true" name="LeasesWeightedAverageDiscountRateAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="hrth_InvestmentGradeMember" abstract="true" name="InvestmentGradeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_FinanceLeaseRightOfUseAssetAccumulatedDepreciation" abstract="false" name="FinanceLeaseRightOfUseAssetAccumulatedDepreciation" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsIntrinsicValueAbstract" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsIntrinsicValueAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="hrth_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceMeasurementPeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceMeasurementPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="hrth_UnvestedSharesMember" abstract="true" name="UnvestedSharesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_QualifiedPlanIIMember" abstract="true" name="QualifiedPlanIIMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_EBITDA" abstract="false" name="EBITDA" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_DefinedBenefitPlanTerminationTerm" abstract="false" name="DefinedBenefitPlanTerminationTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="hrth_RevenueAndCreditConcentrationPolicyPolicyTextBlock" abstract="false" name="RevenueAndCreditConcentrationPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="hrth_PrepaidTaxesAndIncomeTaxesReceivableCurrent" abstract="false" name="PrepaidTaxesAndIncomeTaxesReceivableCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_OmnibusIncentivePlan2005Member" abstract="true" name="OmnibusIncentivePlan2005Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_LeaseLiability" abstract="false" name="LeaseLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_LesseeLeaseRemainingLeaseTerm" abstract="false" name="LesseeLeaseRemainingLeaseTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="hrth_UnbilledReceivablesAndContractWithCustomerAssetAfterAllowanceForCreditLossCurrent" abstract="false" name="UnbilledReceivablesAndContractWithCustomerAssetAfterAllowanceForCreditLossCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_CashFlowLesseeAbstract" abstract="true" name="CashFlowLesseeAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="hrth_WiproMember" abstract="true" name="WiproMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_LesseeOperatingAndFinanceLeasesTextBlock" abstract="false" name="LesseeOperatingAndFinanceLeasesTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="hrth_AuditInformationAbstract" abstract="true" name="AuditInformationAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="hrth_LeaseRightofuseAsset" abstract="false" name="LeaseRightofuseAsset" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodIntrinsicValue" abstract="false" name="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodIntrinsicValue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsAdjustmentAndCorrection" abstract="false" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsAdjustmentAndCorrection" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="hrth_FulfillmentAndLogisticsServicesMember" abstract="true" name="FulfillmentAndLogisticsServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_EmergingMarketsMember" abstract="true" name="EmergingMarketsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_BloombergShorttermBankYieldIndexRateMember" abstract="true" name="BloombergShorttermBankYieldIndexRateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_CustomerPostageAndProgramDeposits" abstract="false" name="CustomerPostageAndProgramDeposits" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_FirstFourAnniversariesMember" abstract="true" name="FirstFourAnniversariesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="hrth_FinanceLeasePaymentsIncludingShortTermLeases" abstract="false" name="FinanceLeasePaymentsIncludingShortTermLeases" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hrth_LeaseLiabilityMaturityTableTextBlock" abstract="false" name="LeaseLiabilityMaturityTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="hrth_NumberOfLeasesImpaired" abstract="false" name="NumberOfLeasesImpaired" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
</xs:schema>
