SC 13D/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO § 240.13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO

§ 240.13d-2(a)

(Amendment No. 5)1

Quantum Corporation (Name of Issuer)

Common Stock, $.001 par value per share

(Title of Class of Securities)

747906 20 4

(CUSIP Number)

ERIC SINGER

VIEX CAPITAL ADVISORS, LLC

825 Third Avenue, 33rd Floor

New York, New York 10022

CHRISTOPHER P. DAVIS, ESQ.

KLEINBERG, KAPLAN, WOLFF & COHEN, P.C.

551 Fifth Avenue, New York, New York 10176

(212) 986-6000

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

June 3, 2016

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box ☐.

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See § 240.13d-7 for other parties to whom copies are to be sent.

_______________

1 The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

1	NAME OF REPORTING PERSON VIEX Opportunities Fund, LP - Series One*
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ☐ (b) ☐
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 7,407,865
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 7,407,865
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 7,407,865
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 2.8%
14	TYPE OF REPORTING PERSON PN

* This Series One is part of a series of VIEX Opportunities Fund, LP, a Delaware series limited partnership.

1	NAME OF REPORTING PERSON VIEX Opportunities Fund, LP - Series Two*
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ☐ (b) ☐
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 1,413,191
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 1,413,191
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,413,191
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) Less than 1%
14	TYPE OF REPORTING PERSON PN

* This Series Two is part of a series of VIEX Opportunities Fund, LP, a Delaware series limited partnership.

1	NAME OF REPORTING PERSON VIEX Special Opportunities Fund III, LP
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ☐ (b) ☐
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 20,710,666
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 20,710,666
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 20,710,666
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 7.8%
14	TYPE OF REPORTING PERSON PN

1	NAME OF REPORTING PERSON VIEX GP, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ☐ (b) ☐
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 8,821,056
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 8,821,056
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 8,821,056
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 3.3%
14	TYPE OF REPORTING PERSON OO

1	NAME OF REPORTING PERSON VIEX Special Opportunities GP III, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ☐ (b) ☐
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 20,710,666
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 20,710,666
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 20,710,666
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 7.8%
14	TYPE OF REPORTING PERSON OO

1	NAME OF REPORTING PERSON VIEX Capital Advisors, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ☐ (b) ☐
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 29,531,722
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 29,531,722
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 29,531,722
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 11.2%
14	TYPE OF REPORTING PERSON IA

1	NAME OF REPORTING PERSON Eric Singer
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ☐ (b) ☐
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION USA
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 29,531,722
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 29,531,722
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 29,531,722
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 11.2%
14	TYPE OF REPORTING PERSON IN

The following constitutes Amendment No.5 to the Schedule 13D filed by the undersigned (the "Amendment No. 5"). This Amendment No. 5 amends the Schedule 13D as specifically set forth herein.

Item 4. Purpose of Transaction.

Item 4 is hereby amended to add the following:

On June 3, 2016, Series One delivered a nomination letter (the "Letter") to the Issuer nominating Mark Bonney, John Mutch, Raghavendra Rau, Khurram Sheikh and Eric Singer (the "Nominees") for election to the Issuer's Board of Directors (the "Board") at the Issuer's 2016 annual meeting of stockholders (the "Annual Meeting") (the "Solicitation"). Series One submitted the Letter because it is disappointed in the Issuer's track record of poor performance and misguided governance. Series One believes reconstituting the Board is the most effective way to drive long-term value and that the Nominees possess the relevant skills and fresh perspectives desperately needed to address the clear performance issues and capital structure challenges facing Quantum, and to oversee a comprehensive, independent and credible strategic assessment of the business with a singular focus on maximizing shareholder value.

Representatives of Series One have engaged, and intend to continue to engage, in discussions with the Board regarding matters relating to unrealized stockholder value, including the composition of the Board.

Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.

Item 6 is hereby amended to add the following:

On June 3, 2016, Series One entered into letter agreements pursuant to which it and its affiliates agreed to indemnify the Nominees  against claims arising from the Solicitation and any related transactions. A form of the indemnification letter agreement is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Item 7. Material to be Filed as Exhibits.

Item 7 is hereby amended to add the following:

99.1	Form of Indemnification Letter Agreement.
99.2	Power of Attorney.

SIGNATURES

After reasonable inquiry and to the best of his knowledge and belief, the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated:  June 6, 2016

VIEX Opportunities Fund, LP - Series One
By:	VIEX GP, LLC General Partner
By:	/s/ Eric Singer
	Name:	Eric Singer
	Title:	Managing Member

VIEX Opportunities Fund, LP - Series Two
By:	VIEX GP, LLC General Partner
By:	/s/ Eric Singer
	Name:	Eric Singer
	Title:	Managing Member

VIEX GP, LLC
By:	/s/ Eric Singer
	Name:	Eric Singer
	Title:	Managing Member

VIEX Special Opportunities Fund II, LP
By:	VIEX Special Opportunities GP II, LLC General Partner
By:	/s/ Eric Singer
	Name:	Eric Singer
	Title:	Managing Member

VIEX Special Opportunities GP II, LLC
By:	/s/ Eric Singer
	Name:	Eric Singer
	Title:	Managing Member

VIEX Capital Advisors, LLC
By:	/s/ Eric Singer
	Name:	Eric Singer
	Title:	Managing Member

/s/ Eric Singer

Eric Singer, individually and as attorney-in-fact for Mark Bonney, John Mutch, Raghavendra Rau and Khurram Sheikh.

EX-99.1

Exhibit 99.1

VIEX OPPORTUNITIES FUND, LP – SERIES ONE825 Third Avenue, 33rd Floor New York, NY 10022

June __, 2016

[______________]

[______________]

[______________]

Re: Quantum Corporation

Dear [______________]:

Thank you for agreeing to serve as a nominee for election to the Board of Directors of Quantum Corporation (the "Company") in connection with the proxy solicitation being considered by VIEX Opportunities Fund, LP – Series One ("VIEX") and certain of its affiliates to nominate and elect directors at the Company's 2016 annual meeting of stockholders, or any other meeting of stockholders held in lieu thereof and any adjournments, postponements, reschedulings or continuations thereof (the "Solicitation"). Your outstanding qualifications, we believe, will prove a valuable asset to the Company and all of its stockholders. This letter ("Agreement") will set forth the terms of our agreement.

VIEX agrees to indemnify and hold you harmless against any and all claims of any nature arising from the Solicitation and any related transactions whenever brought and irrespective of the outcome; provided, however, that you will not be entitled to indemnification for claims arising from your gross negligence, willful misconduct, intentional and material violations of law, criminal actions, provision to VIEX of false or misleading information (including false or misleading information included in (i) any questionnaire you are requested to complete by VIEX, (ii) any resume provided by you to VIEX or (iii) your LinkedIn profile, if available), or material breach of the terms of this Agreement; provided further, that upon your becoming a director of the Company, this indemnification shall not apply to any claims made against you in your capacity as a director of the Company. This indemnification will include any and all losses, liabilities, damages, demands, claims, suits, actions, judgments, or causes of action, assessments, costs and expenses, including, without limitation, interest, penalties, reasonable attorneys' fees, and any and all reasonable costs and expenses incurred in investigating, preparing for or defending against any litigation, commenced or threatened, any civil, criminal, administrative or arbitration action, or any claim whatsoever, and any and all amounts paid in settlement of any claim or litigation asserted against, resulting, imposed upon, or incurred or suffered by you, directly or indirectly, as a result of or arising from the Solicitation and any related transactions (each, a "Loss").

In the event of a claim against you pursuant to the prior paragraph or the occurrence of a Loss, you shall give VIEX prompt written notice of such claim or Loss (provided that failure to promptly notify VIEX shall not relieve it from any liability which it may have on account of this Agreement, except to the extent VIEX shall have been prejudiced by such failure). Upon receipt of such written notice, VIEX will provide you with counsel to represent you. Such counsel shall be reasonably acceptable to you. In addition, you will be reimbursed promptly for all Losses suffered by you and as incurred as provided herein. VIEX may not enter into any settlement of Loss or claim without your consent unless such settlement includes a general release in your favor. Notwithstanding anything to the contrary set forth in this Agreement, VIEX shall not be responsible for any fees, costs or expenses, including for separate legal counsel, incurred by you without VIEX's prior written approval.  In addition, you agree not to enter into any settlement of Loss or claim or make any admission without the written consent of VIEX.

You hereby agree to keep confidential and not disclose to any party, without the consent of VIEX, any confidential, proprietary or non-public information (collectively, "Information") of VIEX or its affiliates which you have heretofore obtained or may obtain. Notwithstanding the foregoing, Information shall not include any information that is publicly disclosed by VIEX or its affiliates or any information that you can demonstrate is now, or hereafter becomes, through no act or failure to act on your part, otherwise generally known to the public.

Notwithstanding the foregoing, if you are required by applicable law, rule, regulation or legal process to disclose any Information you may do so provided that you first promptly notify VIEX so that VIEX may seek a protective order or other appropriate remedy or, in VIEX's sole discretion, waive compliance with the terms of this Agreement. In the event that no such protective order or other remedy is obtained or VIEX does not waive compliance with the terms of this Agreement, you may consult with counsel at the cost of VIEX and you may furnish only that portion of the Information which you are advised by counsel is legally required to be so disclosed and you will request that the party(ies) receiving such Information maintain it as confidential.

All Information, all copies thereof, and any studies, notes, records, analysis, compilations or other documents prepared by you containing such Information, shall be and remain the property of VIEX and, upon the request of a representative of VIEX, all such information shall be returned or, at VIEX's option, destroyed by you, with such destruction confirmed by you to VIEX in writing.

You acknowledge that you are aware that the United States securities laws impose restrictions on the ability of any person who has material non-public information about a company to trade in the securities of such company and to communicate such information to any other person under circumstances in which it is reasonably foreseeable that such person is likely to purchase or sell such securities.

This Agreement shall be governed by the laws of the State of New York, without regard to the principles of the conflicts of laws thereof.  The parties agree to the exclusive jurisdiction of the state and federal courts of New York, New York, and waive, and agree not to plead or to make, any claim that any action or proceeding brought in the state and federal courts of New York, New York has been brought in an improper or inconvenient forum.

THE PARTIES HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT THAT THEY MAY HAVE TO TRIAL BY JURY OF ANY CLAIM OR CAUSE OF ACTION, OR IN ANY LEGAL PROCEEDING, DIRECTLY OR INDIRECTLY BASED UPON OR ARISING OUT OF THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED BY THIS LETTER AGREEMENT (WHETHER BASED ON CONTRACT, TORT OR ANY OTHER THEORY). EACH PARTY HERETO (A) CERTIFIES THAT NO REPRESENTATIVE, AGENT OR ATTORNEY OF THE OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER AND (B) ACKNOWLEDGES THAT IT AND THE OTHER PARTY HAVE BEEN INDUCED TO ENTER INTO THIS LETTER AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS SET FORTH HEREIN.

*          *          *

If you agree to the foregoing terms, please sign below to indicate your acceptance.

VIEX OPPORTUNITIES FUND, LP – SERIES ONE
By:	VIEX GP, LLC General Partner
By:
	Name:	Eric Singer
	Title:	Managing Member

ACCEPTED AND AGREED:

EX-99.2

Exhibit 99.2

POWER OF ATTORNEY

Know all by these presents, that the undersigned hereby constitutes and appoints Eric Singer the undersigned's true and lawful attorney-in-fact to take any and all action in connection with (i) the undersigned's beneficial ownership of, or participation in a group with respect to, securities of Quantum Corporation, a Delaware corporation (the "Company") directly or indirectly beneficially owned by VIEX Opportunities Fund, LP – Series One and its affiliates (collectively, the "Group") and (ii) any proxy solicitation of the Group to elect its slate of director nominees to the board of directors of the Company at the 2016 annual meeting of stockholders of the Company (the "Solicitation"). Such action shall include, but not be limited to:

1. executing for and on behalf of the undersigned any Schedule 13D, and amendments thereto, filed by the Group that are required to be filed under Section 13(d) of the Securities Exchange Act of 1934 (the "Exchange Act") and the rules thereunder in connection with the undersigned's beneficial ownership of, or participation in a group with respect to, securities of the Company or the Solicitation;

2. executing for and on behalf of the undersigned all Forms 3, 4 and 5 required to be filed under Section 16(a) of the Securities Exchange Act of 1934 and the rules thereunder in connection with the undersigned's beneficial ownership of, or participation in a group with respect to, securities of the Company or the Solicitation;

3. executing for and on behalf of the undersigned all Joint Filing and Solicitation Agreements or similar documents pursuant to which the undersigned shall agree to be a member of the Group;

4. performing any and all acts for and on behalf of the undersigned that may be necessary or desirable to complete and execute any such document, complete and execute any amendment or amendments thereto, and timely file such form with the United States Securities and Exchange Commission and any stock exchange or similar authority; and

5. taking any other action of any type whatsoever in connection with the Solicitation, including entering into any settlement agreement, that in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in such attorney-in-fact's discretion.

The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact, or such attorney-in-fact's substitutes, shall lawfully do or cause to be done by virtue of this Power of Attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorneys-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 13(d), Section 16 or Section 14 of the Exchange Act.

This Power of Attorney shall remain in full force and effect until the undersigned is no longer a member of the Group unless earlier revoked by the undersigned in a signed writing delivered to the foregoing attorneys-in-fact.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this ___ day of June 2016.