FORM 4
[ X ] 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
                                                                                  
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
                      

1. Name and Address of Reporting Person *

Smith Jeffrey C 		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 (MM/DD/YYYY)

12/6/2016
(Street)

NEW YORK, NY 10017
(City)        (State)        (Zip)
4. If Amendment, Date Original Filed (MM/DD/YYYY)

 
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. Trans. Date 2A. Deemed Execution Date, if any 3. Trans. 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, $0.01 Par Value   (1) (2) 12/6/2016     S    426649   D $0.92   8316235   I   By Starboard Value and Opportunity Master Fund Ltd   (3)
Common Stock, $0.01 Par Value   (1) (2) 12/6/2016     S    95633   D $0.92   1864087   I   By Starboard Value and Opportunity S LLC   (4)
Common Stock, $0.01 Par Value   (1) (2) 12/6/2016     S    78079   D $0.92   1521923   I   By Starboard Value and Opportunity C LP   (5)
Common Stock, $0.01 Par Value   (1) (2) 12/6/2016     S    149639   D $0.92   2916751   I   By Managed Account of Starboard Value LP   (6)
Common Stock, $0.01 Par Value   (1) (2) 12/6/2016     S    4038941   D $0.9103   4277294   I   By Starboard Value and Opportunity Master Fund Ltd   (3)
Common Stock, $0.01 Par Value   (1) (2) 12/6/2016     S    905330   D $0.9103   958757   I   By Starboard Value and Opportunity S LLC   (4)
Common Stock, $0.01 Par Value   (1) (2) 12/6/2016     S    739152   D $0.9103   782771   I   By Starboard Value and Opportunity C LP   (5)
Common Stock, $0.01 Par Value   (1) (2) 12/6/2016     S    1416577   D $0.9103   1500174   I   By Managed Account of Starboard Value LP   (6)

Table II - Derivative Securities Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security
(Instr. 3) 		2. Conversion or Exercise Price of Derivative Security 3. Trans. Date 3A. Deemed Execution Date, if any 4. Trans. 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 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 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

Explanation of Responses:
( 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 second 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.

Reporting Owners
Reporting Owner Name / Address
Relationships
Director 10% Owner Officer Other
Smith Jeffrey C
777 THIRD AVENUE, 18TH FLOOR
NEW YORK, NY 10017
X
See Footnote 2
MITCHELL MARK R
777 THIRD AVENUE, 18TH FLOOR
NEW YORK, NY 10017
X
See Footnote 2
Feld Peter A
777 THIRD AVENUE, 18TH FLOOR
NEW YORK, NY 10017
X
See Footnote 2

Signatures
By: /s/ Jeffrey C. Smith 12/7/2016
** Signature of Reporting Person Date

Mark R. Mitchell; By: /s/ Jeffrey C. Smith, Attorney in Fact 12/7/2016
** Signature of Reporting Person Date

Peter A. Feld; By: /s/ Jeffrey C. Smith, Attorney in Fact 12/7/2016
** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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.