Ownership Submission

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 OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person ^*

Starboard Value LP

2. Issuer Name and Ticker or Trading Symbol
QUANTUM CORP /DE/ [QTM]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

_____ Director	__X__ 10% Owner
_____ Officer (give title below)	__X__ Other (specify below)
See Footnote 2

(Last)

(First)

(Middle)

777 THIRD AVENUE, 18TH FLOOR

3. Date of Earliest Transaction (Month/Day/Year)
12/06/2016

(Street)

NEW YORK, NY 10017

4. If Amendment, Date 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

(City)

(State)

(Zip)

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)
1.Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock, $0.01 Par Value ⁽¹⁾ ⁽²⁾	12/06/2016		S		426,649	D	$ 0.92	8,316,235	I	By Starboard Value and Opportunity Master Fund Ltd ⁽³⁾
Common Stock, $0.01 Par Value ⁽¹⁾ ⁽²⁾	12/06/2016		S		95,633	D	$ 0.92	1,864,087	I	By Starboard Value and Opportunity S LLC ⁽⁴⁾
Common Stock, $0.01 Par Value ⁽¹⁾ ⁽²⁾	12/06/2016		S		78,079	D	$ 0.92	1,521,923	I	By Starboard Value and Opportunity C LP ⁽⁵⁾
Common Stock, $0.01 Par Value ⁽¹⁾ ⁽²⁾	12/06/2016		S		149,639	D	$ 0.92	2,916,751	I	By Managed Account of Starboard Value LP ⁽⁶⁾
Common Stock, $0.01 Par Value ⁽¹⁾ ⁽²⁾	12/06/2016		S		4,038,941	D	$ 0.9103	4,277,294	I	By Starboard Value and Opportunity Master Fund Ltd ⁽³⁾
Common Stock, $0.01 Par Value ⁽¹⁾ ⁽²⁾	12/06/2016		S		905,330	D	$ 0.9103	958,757	I	By Starboard Value and Opportunity S LLC ⁽⁴⁾
Common Stock, $0.01 Par Value ⁽¹⁾ ⁽²⁾	12/06/2016		S		739,152	D	$ 0.9103	782,771	I	By Starboard Value and Opportunity C LP ⁽⁵⁾
Common Stock, $0.01 Par Value ⁽¹⁾ ⁽²⁾	12/06/2016		S		1,416,577	D	$ 0.9103	1,500,174	I	By Managed Account of Starboard Value LP ⁽⁶⁾

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.		SEC 1474 (9-02)

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 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

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Starboard Value LP 777 THIRD AVENUE 18TH FLOOR NEW YORK, NY 10017		X		See Footnote 2
Starboard Value GP LLC 777 THIRD AVENUE 18TH FLOOR NEW YORK, NY 10017		X		See Footnote 2
STARBOARD VALUE & OPPORTUNITY S LLC 777 THIRD AVENUE 18TH FLOOR NEW YORK, NY 10017		X		See Footnote 2
Starboard Principal Co LP 777 THIRD AVENUE 18TH FLOOR NEW YORK, NY 10017		X		See Footnote 2
Starboard Principal Co GP LLC 777 THIRD AVENUE 18TH FLOOR NEW YORK, NY 10017		X		See Footnote 2
STARBOARD VALUE & OPPORTUNITY MASTER FUND LTD 777 THIRD AVENUE 18TH FLOOR NEW YORK, NY 10017		X		See Footnote 2
Starboard Value & Opportunity C LP 777 THIRD AVENUE 18TH FLOOR NEW YORK, NY 10017		X		See Footnote 2
Starboard Value R LP 777 THIRD AVENUE 18TH FLOOR NEW YORK, NY 10017		X		See Footnote 2
Starboard Value R GP LLC 777 THIRD AVENUE 18TH FLOOR NEW YORK, NY 10017		X		See Footnote 2

Signatures

Starboard Value LP; By: Starboard Value GP LLC; By: /s/ Jeffrey C. Smith, Authorized Signatory		12/07/2016
^**Signature of Reporting Person		Date
Starboard Value and Opportunity Master Fund Ltd; By: Starboard Value LP; By: /s/ Jeffrey C. Smith, Authorized Signatory		12/07/2016
^**Signature of Reporting Person		Date
Starboard Value and Opportunity S LLC; By: Starboard Value LP; By: /s/ Jeffrey C. Smith, Authorized Signatory		12/07/2016
^**Signature of Reporting Person		Date
Starboard Value and Opportunity C LP; By: Starboard Value LP; By: /s/ Jeffrey C. Smith, Authorized Signatory		12/07/2016
^**Signature of Reporting Person		Date
Starboard Value GP LLC; By: Starboard Principal Co LP; By: /s/ Jeffrey C. Smith, Authorized Signatory		12/07/2016
^**Signature of Reporting Person		Date
Starboard Principal Co LP; By:Starboard Principal Co GP LLC; By: /s/ Jeffrey C. Smith, Authorized Signatory		12/07/2016
^**Signature of Reporting Person		Date
Starboard Principal Co GP LLC; By: /s/ Jeffrey C. Smith, Authorized Signatory		12/07/2016
^**Signature of Reporting Person		Date
Starboard Value R LP; By: /s/ Jeffrey C. Smith, Authorized Signatory		12/07/2016
^**Signature of Reporting Person		Date
Starboard Value R GP LLC; By: /s/ Jeffrey C. Smith, Authorized Signatory		12/07/2016
^**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	This Form 4 is filed jointly by Starboard Value and Opportunity Master Fund Ltd ("Starboard V&O Fund"), Starboard Value and Opportunity S LLC ("Starboard S LLC"), Starboard Value and Opportunity C LP ("Starboard C LP"), Starboard Value LP ("Starboard Value LP"), Starboard Value GP LLC ("Starboard Value GP"), Starboard Principal Co LP ("Principal Co"), Starboard Principal Co GP LLC ("Principal GP"), Starboard Value R LP ("Starboard R LP"), Starboard Value R GP LLC ("Starboard R GP"), Jeffrey C. Smith, Mark R. Mitchell and Peter A. Feld (collectively, the "Reporting Persons"). To enable all of the Reporting Persons to gain access to the Securities and Exchange Commission's electronic filing system (which only accepts a maximum of 10 joint filers per report), this report is the first of two identical reports relating to the same transactions being filed with the Securities and Exchange Commission.
(2)	Each Reporting Person may be deemed to be a member of a Section 13(d) group that previously owned more than 10% of the Issuer's outstanding shares of Common Stock. As of December 6, 2016, the Reporting Persons ceased to own 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)	Shares of Common Stock beneficially owned by Starboard V&O Fund. Starboard Value LP, as the investment manager of Starboard V&O Fund, may be deemed to be the beneficial owner of the shares of Common Stock beneficially owned by Starboard V&O Fund. Each of Starboard Value GP, as the general partner of Starboard Value LP, Principal Co, as a member of Starboard Value GP, Principal GP, as the general partner of Principal Co, and Messrs. Smith, Mitchell and Feld, as members of Principal GP and as members of each of the Management Committee of Starboard Value GP and the Management Committee of Principal GP, may be deemed to be the beneficial owner of the shares of Common Stock beneficially owned by Starboard V&O Fund.
(4)	Shares of Common Stock beneficially owned by Starboard S LLC. Starboard Value LP, as the manager of Starboard S LLC, may be deemed to be the beneficial owner of the shares of Common Stock beneficially owned by Starboard S LLC. Each of Starboard Value GP, as the general partner of Starboard Value LP, Principal Co, as a member of Starboard Value GP, Principal GP, as the general partner of Principal Co, and Messrs. Smith, Mitchell and Feld, as members of Principal GP and as members of each of the Management Committee of Starboard Value GP and the Management Committee of Principal GP, may be deemed to be the beneficial owner of the shares of Common Stock beneficially owned by Starboard S LLC.
(5)	Shares of Common Stock beneficially owned by Starboard C LP. Each of Starboard R LP, as the general partner of Starboard C LP, and Starboard R GP, as the general partner of Starboard R LP, may be deemed to be the beneficial owner of the shares of Common Stock beneficially owned by Starboard C LP. Starboard Value LP, as the investment manager of Starboard C LP, may be deemed to be the beneficial owner of the shares of Common Stock beneficially owned by Starboard C LP. Each of Starboard Value GP, as the general partner of Starboard Value LP, Principal Co, as a member of Starboard Value GP, Principal GP, as the general partner of Principal Co, and Messrs. Smith, Mitchell and Feld, as members of Principal GP and as members of each of the Management Committee of Starboard Value GP and the Management Committee of Principal GP, may be deemed to be the beneficial owner of the shares of Common Stock beneficially owned by Starboard C LP.
(6)	Shares held in an account managed by Starboard Value LP. Starboard Value GP, as the general partner of Starboard Value LP, Principal Co, as a member of Starboard Value GP, Principal GP, as the general partner of Principal Co, and Messrs. Smith, Mitchell and Feld as members of Principal GP and as members of each of the Management Committee of Starboard Value GP and the Management Committee of Principal GP, may be deemed to be the beneficial owner of the shares of Common Stock beneficially owned by Starboard Value LP.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.