13D Filing: Starboard Value LP and Quantum Corp (QTM)

The following constitutes
Amendment No. 9 to the Schedule 13D filed by the undersigned (“Amendment No. 9”). This Amendment No. 9 amends the Schedule
13D as specifically set forth herein.

Item 3.

Source and Amount of Funds or Other Consideration.

Item 3 is hereby amended and restated to read
as follows:

The Shares purchased by each
of Starboard V&O Fund, Starboard S LLC and Starboard C LP and held in the Starboard Value LP Account were purchased with working
capital (which may, at any given time, include margin loans made by brokerage firms in the ordinary course of business) in open
market purchases, except as otherwise noted, as set forth in Schedule A to the Schedule 13D, which is incorporated by reference
herein.  The aggregate purchase price of the 534,661 Shares beneficially owned by Starboard V&O Fund is approximately
$5,366,216, excluding brokerage commissions.  The aggregate purchase price of the 119,844 Shares beneficially owned by
Starboard S LLC is approximately $1,221,762, excluding brokerage commissions.   The aggregate purchase price of the 97,846
Shares beneficially owned by Starboard C LP is approximately $954,981, excluding brokerage commissions.  The aggregate
purchase price of the 187,521 Shares held in the Starboard Value LP Account is approximately $1,911,866, excluding brokerage commissions.

The 17,195 Shares beneficially
owned by Mr. Smith represent restricted stock units (“RSUs”) that have vested, which were granted to Mr. Smith as compensation
for his service on the Board of Directors of the Issuer.

Item 5.

Interest in Securities of the Issuer.

Item 5 is hereby amended
and restated to read as follows:

The aggregate percentage
of Shares reported owned by each Reporting Person is based upon 34,673,884 Shares outstanding, which is the total number of Shares
outstanding as of November 3, 2017 as reported in the Issuer’s Quarterly Report on Form 10-Q, filed with the Securities and
Exchange Commission on November 9, 2017.

A.

Starboard V&O Fund

(a)

As of the close of business on November 15, 2017, Starboard V&O Fund beneficially owned 534,661 Shares.

Percentage: Approximately 1.5%

(b)

1. Sole power to vote or direct vote: 534,661 2. Shared power to vote or direct vote: 0 3. Sole power to dispose or direct the disposition: 534,661 4. Shared power to dispose or direct the disposition: 0

(c)

Other than the Notes having matured (as defined and described in Item 6 below), Starboard V&O Fund has not transacted in the Shares during the past sixty days.

B.

Starboard S LLC

(a)

As of the close of business on November 15, 2017, Starboard S LLC beneficially owned 119,844 Shares.

Percentage: Less than 1%