SEC Form 4

FORM 4		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 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
X	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Singer Eric (Last) (First) (Middle) 745 BOYLSTON STREET 3RD FLOOR (Street) BOSTON MA 02116 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol QUANTUM CORP /DE/ [ QMCO ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses
	3. Date of Earliest Transaction (Month/Day/Year) 12/10/2019
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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, par value $0.001(1)(2)								66,681(3)	D
Common Stock, par value $0.001(1)(2)	12/10/2019		S		90,304	D	$5.775	835,679	I	By Viex Opportunities Fund, LP - Series One(4)
Common Stock, par value $0.001(1)(2)	12/10/2019		S		17,227	D	$5.775	159,421	I	By Viex Opportunities Fund, LP - Series Two(5)
Common Stock, par value $0.001(1)(2)	12/10/2019		S		252,469	D	$5.775	2,336,364	I	By Viex Special Opportunities Fund III, LP(6)

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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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

1. Name and Address of Reporting Person* Singer Eric (Last) (First) (Middle) 745 BOYLSTON STREET 3RD FLOOR (Street) BOSTON MA 02116 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* VIEX Opportunities Fund, LP Series One (Last) (First) (Middle) 745 BOYLSTON STREET 3RD FLOOR (Street) BOSTON MA 02116 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* VIEX Opportunities Fund, LP - Series Two (Last) (First) (Middle) 745 BOYLSTON STREET 3RD FLOOR (Street) BOSTON MA 02116 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* VIEX Special Opportunities Fund III, LP (Last) (First) (Middle) 745 BOYLSTON STREET 3RD FLOOR (Street) BOSTON NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* VIEX GP, LLC (Last) (First) (Middle) 745 BOYLSTON STREET 3RD FLOOR (Street) BOSTON NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* VIEX Special Opportunities GP III, LLC (Last) (First) (Middle) 745 BOYLSTON STREET 3RD FLOOR (Street) BOSTON NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* VIEX Capital Advisors, LLC (Last) (First) (Middle) 745 BOYLSTON STREET 3RD FLOOR (Street) BOSTON MA 02116 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

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 Fund, LP - Series Two ("Series Two"), a series of VIEX Opportunities Fund, LP, 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. As of the close of business on December 10, 2019, the Reporting Persons ceased to be holders of an aggregate of 10% or more of Quantum Corporation's (the "Issuer") outstanding shares of Common Stock. Each Reporting Person disclaims beneficial ownership of the securities of the Issuer 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 securities for purposes of Section 16 or for any other purpose.

3. Each share is represented by a restricted stock unit, all of which are fully vested and each of which represents a contingent right to receive one share of common stock of the Issuer.

4. Securities of the Issuer beneficially owned directly by Series One. VIEX GP, as the general partner of Series One, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by Series One. VIEX Capital, as the investment manager of Series One, may be deemed the beneficial owner of the securities of the Issuer 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 securities of the Issuer beneficially owned by Series One.

5. Securities of the Issuer beneficially owned directly by Series Two. VIEX GP, as the general partner of Series Two, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by Series Two. VIEX Capital, as the investment manager of Series Two, may be deemed the beneficial owner of the securities of the Issuer 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 securities of the Issuer beneficially owned by Series Two.

6. Securities of the Issuer beneficially owned directly by VSO III. VSO GP III, as the general partner of VSO III, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by VSO III. VIEX Capital, as the investment manager of VSO III, may be deemed the beneficial owner of the securities of the Issuer 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 securities of the Issuer beneficially owned by VSO III.

	ERIC SINGER, Name: /s/ Eric Singer	12/12/2019
	VIEX OPPORTUNITIES FUND, LP - SERIES ONE, By: VIEX GP, LLC, its General Partner, Name: /s/ Eric Singer, Title: Managing Member	12/12/2019
	VIEX OPPORTUNITIES FUND, LP - SERIES TWO, By: VIEX GP, LLC, its General Partner, Name: /s/ Eric Singer, Title: Managing Member	12/12/2019
	VIEX SPECIAL OPPORTUNITIES FUND III, LP, By: VIEX Special Opportunities GP III, LLC, its General Partner, Name: /s/ Eric Singer, Title: Managing Member	12/12/2019
	VIEX GP, LLC, Name: /s/ Eric Singer, Title: Managing Member	12/12/2019
	VIEX SPECIAL OPPORTUNITIES GP III, LLC, Name: /s/ Eric Singer, Title: Managing Member	12/12/2019
	VIEX CAPITAL ADVISORS, LLC, Name: /s/ Eric Singer, Title: Managing Member	12/12/2019
	** Signature of Reporting Person	Date
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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