<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2010-08-20</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001164552</issuerCik>
        <issuerName>CDSS Wind Down Inc</issuerName>
        <issuerTradingSymbol>CWDW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001496732</rptOwnerCik>
            <rptOwnerName>Samuel Michael</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O GREEN ENERGY MANAGEMENT SERVICES INC</rptOwnerStreet1>
            <rptOwnerStreet2>381 TEANECK ROAD</rptOwnerStreet2>
            <rptOwnerCity>TEANECK</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07666</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman, President, and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, $0.0001 par value</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">In connection with the Merger Agreement, dated as of March 29, 2010, as amended, by and among Green Energy Management Services, Inc. (&quot;GEM&quot;), the Issuer, and the Issuer's wholly-owned merger subsidiary (the &quot;Merger Subsidiary&quot;), CDSS Merger Corporation, pursuant to which on August 20, 2010, the Merger Subsidiary merged with and into GEM, with GEM being the surviving corporation, and became a wholly-owned subsidiary of the Issuer, the Reporting Person was appointed the Chairman, President and Chief Executive Officer and a director of the Issuer.</footnote>
        <footnote id="F2">Although Mr. Samuel does not have direct beneficial ownership of any of the Issuer's shares of common stock, his wife and son are the sole members of GEM Lighting, L.L.C., which beneficially owns 65,623,216 post-reverse stock split shares of the Issuer's common stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Robert Weinstein, as attorney-in-fact for Michael Samuel</signatureName>
        <signatureDate>2010-08-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
