Filing Details

CUSIP No. 747906 20 4

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

CUSIP No. 747906 20 4

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

CUSIP No. 747906 20 4

CUSIP No. 747906 20 4

CUSIP No. 747906 20 4

CUSIP No. 747906 20 4

CUSIP No. 747906 20 4

The following constitutes Amendment No. 6 to the Schedule 13D filed by the undersigned (the "Amendment No. 6"). This Amendment No. 6 amends the Schedule 13D as specifically set forth herein.

Item 4.

Purpose of Transaction.

Item 4 is hereby amended to add the following:

On September 23, 2016, the Issuer entered into an agreement (the "Agreement") with the Reporting Persons. Under the Agreement, the Issuer has granted Board observer rights to John Mutch and Raghavendra Rau until December 1, 2016, subject to certain conditions. In addition, the Issuer will use its reasonable best efforts to hold its Annual Meeting of Stockholders on January 31, 2017, or another date mutually agreed by the parties.

Under the Agreement, the Reporting Persons have agreed to abide by certain standstill provisions related to the solicitation of proxies and other matters until December 1, 2016, subject to earlier termination under certain circumstances. The foregoing description of the Agreement is qualified in its entirety by reference to the Agreement, which is attached as Exhibit 99.1 hereto and incorporated herein by reference.

Item 5.

Interest in Securities of the Issuer.

	(a)		As of the date hereof, Series One beneficially owned 7,407,865 Shares.
			Percentage: Approximately 2.8%
	(b)	1.	Sole power to vote or direct vote: 0
		2.	Shared power to vote or direct vote: 7,407,865
		3.	Sole power to dispose or direct the disposition: 0
		4.	Shared power to dispose or direct the disposition: 7,407,865
	(c)		Series One has not entered into any transactions during the past 60 days.

	(a)		As of the date hereof, Series Two beneficially owned 1,413,191 Shares.
			Percentage: Less than 1%
	(b)	1.	Sole power to vote or direct vote: 0
		2.	Shared power to vote or direct vote: 1,413,191
		3.	Sole power to dispose or direct the disposition: 0
		4.	Shared power to dispose or direct the disposition: 1,413,191
	(c)		Series Two has not entered into any transactions during the past 60 days.

C.

VSO III

D.

VIEX GP

E.	VSO GP III

F.	VIEX Capital

G.	Eric Singer

The filing of this Schedule 13D shall not be construed as an admission that the Reporting Persons are, for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, the beneficial owners of any of the Shares reported herein. Each Reporting Person disclaims beneficial ownership of such Shares except to the extent of his or its pecuniary interest therein.

Item 6.

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

Item 6 is hereby amended to add the following:

On September 23, 2016, the Reporting Persons and the Issuer entered into the Agreement defined and described in Item 4 above and attached as Exhibit 99.1 hereto.

Item 7.

Material to be Filed as Exhibits.

Item 7 is hereby amended to add the following Exhibit:

Exhibit 99.1 -

Agreement, made and entered into as of September 23, 2016, by and among Quantum Corporation and the entities and natural persons listed on Exhibit A thereto (incorporated by reference to Exhibit 10.1 to the Issuer's Current Report on Form 8-K filed September 26, 2016) (File No. 001-13449).

SIGNATURES

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

Dated:

September 27, 2016