Sec Form 4 Filing - Singer Eric @ QUANTUM CORP /DE/ - 2017-12-01

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Singer Eric 2. Issuer Name and Ticker or Trading Symbol QUANTUM CORP /DE/ [ QTM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 825 THIRD AVENUE, 33RD FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 12/01/2017 (Street) NEW YORK, NY10022 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock ( 1 ) ( 2 ) 12/01/2017 A 16,681 ( 3 ) A $ 0 16,681 ( 4 ) ( 5 ) D Common Stock ( 1 ) ( 2 ) 925,983 ( 4 ) I By: VIEX Opportunities Fund, LP - Series One ( 6 ) Common Stock ( 1 ) ( 2 ) 176,648 ( 4 ) I By: VIEX Opportunities Fund, LP - Series Two ( 7 ) Common Stock ( 1 ) ( 2 ) 2,588,833 ( 4 ) I By: VIEX Special Opportunities Fund III, LP ( 8 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Singer Eric 825 THIRD AVENUE 33RD FLOOR NEW YORK, NY10022 X X VIEX Opportunities Fund, LP Series One 825 THIRD AVENUE 33RD FLOOR NEW YORK, NY10022 X VIEX Opportunities Fund, LP Series Two 825 THIRD AVENUE 33RD FLOOR NEW YORK, NY10022 X VIEX Special Opportunities Fund III, LP 825 THIRD AVENUE 33RD FLOOR NEW YORK, NY10022 X VIEX Special Opportunities GP III, LLC 825 THIRD AVENUE 33RD FLOOR NEW YORK, NY10022 X VIEX GP, LLC 825 THIRD AVENUE 33RD FLOOR NEW YORK, NY10022 X VIEX Capital Advisors, LLC 825 THIRD AVENUE 33RD FLOOR NEW YORK, NY10022 X Signatures */s/ Astrid Becker-Celik, Attorney in Fact for Eric Singer 12/04/2017 Signature of Reporting Person Date VIEX Opportunities Fund, LP - Series One; By: VIEX GP, LLC; its general partner; By: /s/ *, Managing Member 12/04/2017 Signature of Reporting Person Date VIEX Opportunities Fund, LP - Series Two; By: VIEX GP, LLC; its general partner; By: /s/ *, Managing Member 12/04/2017 Signature of Reporting Person Date VIEX Special Opportunities Fund III, LP; By: VIEX Special Opportunities GP III, LLC; its general partner; By: /s/ *, Managing Member 12/04/2017 Signature of Reporting Person Date VIEX Special Opportunities GP III, LLC; By /s/ *, Managing Member 12/04/2017 Signature of Reporting Person Date VIEX GP, LLC; By: /s/ *, Managing Member 12/04/2017 Signature of Reporting Person Date VIEX Capital Advisors, LLC; By /s/ *, Managing Member 12/04/2017 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This Form 4 is filed jointly by VIEX Opportunities Fund, LP - Series One ("Series One"), a series of VIEX Opportunities Fund, LP ("VIEX Opportunities"), a series limited partnership, VIEX Opportunities Fund, LP - Series Two ("Series Two"), a series of VIEX Opportunities, VIEX Special Opportunities Fund III, LP ("VSO III"), VIEX GP, LLC ("VIEX GP"), VIEX Special Opportunities GP III, LLC ("VSO GP III"), VIEX Capital Advisors, LLC ("VIEX Capital"), and Eric Singer (collectively, the "Reporting Persons"). ( 2 )The Reporting Persons are filing this report because each of the Reporting Persons is a member of a Section 13(d) group, disclosed in a Schedule 13D filed on behalf of the Reporting Persons, as it may be amended, which beneficially owns in the aggregate more than 10% of the Issuer's outstanding shares of Common Stock. Each Reporting Person disclaims beneficial ownership of the shares of Common Stock reported herein except to the extent of his or its pecuniary interest therein, and this report shall not be deemed to be an admission that any Reporting Person is the beneficial owner of such shares of Common Stock for purposes of Section 16 or for any other purpose. ( 3 )Restricted stock units will fully vest on the earlier to occur of: i) the date of Quantum Corporation's next Annual Stockholder Meeting; and ii) September 1, 2018. ( 4 )Reflects a 1-for-8 reverse stock split of the Issuer's common stock effected on April 18, 2017. ( 5 )Mr. Singer, as the managing member of VIEX GP and VIEX Capital, may be deemed the beneficial owner of the (i) 925,983 Shares owned by Series One, (ii) 176,648 Shares owned by Series Two and (iii) 2,588,833 owned by VSO III. ( 6 )Shares of Common Stock beneficially owned directly by Series One. VIEX GP, as the general partner of Series One, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series One. VIEX Capital, as the investment manager of Series One, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series One. Mr. Singer, as the managing member of each of VIEX GP and VIEX Capital, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series One. ( 7 )Shares of Common Stock beneficially owned directly by Series Two. VIEX GP, as the general partner of Series Two, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series Two. VIEX Capital, as the investment manager of Series Two, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series Two. Mr. Singer, as the managing member of each of VIEX GP and VIEX Capital, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series Two. ( 8 )Shares of Common Stock beneficially owned directly by VSO III. VSO GP III, as the general partner of VSO III, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by VSO III. VIEX Capital, as the investment manager of VSO III, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by VSO III. Mr. Singer, as the managing member of each of VSO GP III and VIEX Capital, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by VSO III.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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