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<?xml version="1.0" encoding="windows-1252"?> |
<ownershipDocument> |
| <schemaVersion> X0306 </schemaVersion> |
| <documentType> 4 </documentType> |
| <periodOfReport> 2022-09-09 </periodOfReport> |
| <notSubjectToSection16> 0 </notSubjectToSection16> |
| <issuer> |
| | <issuerCik> 0000709283 </issuerCik> |
| | <issuerName> QUANTUM CORP /DE/ </issuerName> |
| | <issuerTradingSymbol> QMCO </issuerTradingSymbol> |
| | </issuer> |
| <reportingOwner> |
| | <reportingOwnerId> |
| | | <rptOwnerCik> 0001597383 </rptOwnerCik> |
| | | <rptOwnerName> Moorehead Lewis W. </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> 0 </isDirector> |
| | | <isOfficer> 1 </isOfficer> |
| | | <isTenPercentOwner> 0 </isTenPercentOwner> |
| | | <isOther> 0 </isOther> |
| | | <officerTitle> Chief Accounting Officer </officerTitle> |
| | | <otherText></otherText> |
| | | </reportingOwnerRelationship> |
| | </reportingOwner> |
| <nonDerivativeTable> |
| | <nonDerivativeTransaction> |
| | | <securityTitle> |
| <value> Common Stock </value> |
| </securityTitle> |
| | | <transactionDate> |
| <value> 2022-09-09 </value> |
| </transactionDate> |
| | | <transactionCoding> |
| <transactionFormType> 4 </transactionFormType> |
| <transactionCode> S </transactionCode> |
| <equitySwapInvolved> 0 </equitySwapInvolved> |
| </transactionCoding> |
| | | <transactionAmounts> |
| <transactionShares> |
| <value> 8416 </value> |
| <footnoteId id="F1"/> |
| </transactionShares> |
| <transactionPricePerShare> |
| <value> 1.5696 </value> |
| </transactionPricePerShare> |
| <transactionAcquiredDisposedCode> |
| <value> D </value> |
| </transactionAcquiredDisposedCode> |
| </transactionAmounts> |
| | | <postTransactionAmounts> |
| <sharesOwnedFollowingTransaction> |
| <value> 203923 </value> |
| <footnoteId id="F2"/> |
| </sharesOwnedFollowingTransaction> |
| </postTransactionAmounts> |
| | | <ownershipNature> |
| <directOrIndirectOwnership> |
| <value> D </value> |
| </directOrIndirectOwnership> |
| </ownershipNature> |
| | | </nonDerivativeTransaction> |
| | </nonDerivativeTable> |
| <derivativeTable></derivativeTable> |
| <footnotes> |
| | <footnote id="F1"> Represents the number of shares automatically sold, on a non-discretionary basis, to cover tax withholding obligations in connection with the vesting of restricted stock units and performance-based stock units granted on September 6, 2019. </footnote> |
| | <footnote id="F2"> Includes 1,577 shares acquired under Quantum Corporation's Employee Stock Purchase Plan on August 5, 2022. </footnote> |
| | </footnotes> |
| <remarks></remarks> |
| <ownerSignature> |
| | <signatureName> /s/ Josie Buensuceso, Attorney-in-Fact for Lewis W. Moorehead </signatureName> |
| | <signatureDate> 2022-09-12 </signatureDate> |
| | </ownerSignature> |
| </ownershipDocument> |