Amendment No. 1 to Rights Agreement, dated as of November 16, 2020, between Commvault Systems, Inc. and Computershare Trust Company, N.A., as Rights Agent

“Acquiring Person” shall mean any Person (as such term is hereinafter defined) who or which, together with all Affiliates and Associates of such Person, shall be the Beneficial Owner (as such term is hereinafter defined) of 10% or more of the shares of Common Stock then outstanding, but shall not include (i) an Exempt Person (as such term is hereinafter defined), (ii) a Passive Institutional Investor (as such term is hereinafter defined), so long as, in the case of this clause (ii), such Person is not the Beneficial Owner of 20% or more of the shares of Common Stock then outstanding, but subject to the provisions in the definition of “Passive Institutional Investor” or (iii) Starboard (as such term is hereinafter defined), so long as, in the case of this clause (iii), Starboard is not the Beneficial Owner of 15% or more of the shares of Common Stock then outstanding; provided, however, that

(i)    if the Board of Directors of the Company determines that a Person who would otherwise be an “Acquiring Person” became the Beneficial Owner of a number of shares of Common Stock such that the Person would otherwise qualify as an “Acquiring Person” inadvertently (including because (A) such Person was unaware that it beneficially owned that number of shares of Common Stock that would otherwise cause such Person to be an “Acquiring Person” or (B) such Person was aware of the extent of its Beneficial Ownership of Common Stock but had no actual knowledge of the consequences of such Beneficial Ownership under this Agreement) and without any intention of obtaining, changing or influencing control of the Company, then such Person shall not be deemed to be or to have become an “Acquiring Person” for any purposes of this Agreement unless and until such Person shall have failed to divest itself, as soon as practicable (as determined by the Board of Directors of the Company), of Beneficial Ownership of a sufficient number of shares of Common Stock so that such Person would no longer otherwise qualify as an “Acquiring Person”;

(ii)    if, as of the date hereof or prior to the first public announcement of the adoption of this Agreement, any Person (together with its Affiliates and Associates) is or becomes the Beneficial Owner of 10% (20% in the case of a Passive Institutional Investor) or more of the shares of Common Stock outstanding, such Person shall not be deemed to be or to become an “Acquiring Person” unless and until such time as such Person shall, after the first public announcement of the adoption of this Agreement, become the Beneficial Owner of any additional shares of Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding Common Stock or pursuant to a split or subdivision of the outstanding Common Stock) that would cause such Person’s Beneficial Ownership of the Common Stock outstanding to exceed by any amount such Person’s Beneficial Ownership as of the date of this Agreement, in which case such Person will become an Acquiring Person;

(iii)    no Person shall become an “Acquiring Person” solely as a result of any unilateral grant of any security by the Company or through the exercise of any options, warrants, rights or similar interests (including restricted stock) granted by the Company to its directors, officers and employees;

(iv)    no Person shall become an “Acquiring Person” solely as the result of an acquisition of shares of Common Stock by

the Company which, by reducing the number of shares of Common Stock outstanding, increases the proportion of the shares of Common Stock beneficially owned by such Person to 10% (15% in the case of Starboard or 20% in the case of a Passive Institutional Investor) or more of the Common Stock then outstanding; provided, however, that if a Person shall become the Beneficial Owner of 10% (15% in the case of Starboard or 20% in the case of a Passive Institutional Investor) or more of the shares of Common Stock then outstanding by reason of such share acquisitions by the Company and shall thereafter become the Beneficial Owner of any additional shares of Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding Common Stock or pursuant to a split or subdivision of the outstanding Common Stock), then such Person shall be deemed to be an “Acquiring Person” unless, upon becoming the Beneficial Owner of such additional shares of Common Stock, such Person does not beneficially own 10% (15% in the case of Starboard or 20% in the case of a Passive Institutional Investor) or more of the shares of Common Stock then outstanding; and

(v)    no Person shall become an “Acquiring Person” solely as the result of the acquisition by such Person of Beneficial Ownership of shares of Common Stock from an individual who, on the later of the date hereof and the first public announcement of this Agreement, is the Beneficial Owner of 10% (15% in the case of Starboard or 20% in the case of a Passive Institutional Investor) or more of the Common Stock then outstanding if such shares of Common Stock are received by such Person upon such individual’s death pursuant to such individual’s will or pursuant to a charitable trust created by such individual for estate planning purposes unless and until such time as such Person shall become the Beneficial Owner of any additional shares of Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding Common Stock or pursuant to a split or subdivision of the outstanding Common Stock), unless, upon becoming the Beneficial Owner of such additional shares of Common Stock, such Person is not then the Beneficial Owner of 10% (15% in the case of Starboard or 20% in the case of a Passive Institutional Investor) or more of the shares of Common Stock then outstanding.

With respect to any Person, for all purposes of this Agreement, any calculation of the number of shares of Common Stock outstanding at any particular time, including for purposes of determining the particular percentage of the outstanding shares of Common Stock of which such Person is the Beneficial Owner, shall include the number of shares of

Common Stock not outstanding at the time of such calculation that such Person is otherwise deemed to beneficially own for purposes of this Agreement, but the number of shares of Common Stock not outstanding that such Person is otherwise deemed to beneficially own for purposes of this Agreement shall not be included for the purpose of computing the percentage of the outstanding shares of Common Stock beneficially owned by any other Person (unless such other Person is also otherwise deemed to beneficially own for purposes of this Agreement such shares of Common Stock not outstanding).

“Starboard” shall mean, collectively, (i) Starboard Value and Opportunity Master Fund Ltd, (ii) Starboard Value and Opportunity S LLC, (iii) Starboard Value and Opportunity C LP, (iv) Starboard Value R LP, (v) Starboard Value and Opportunity Master Fund L LP, (vi) Starboard Value L LP, (vii) Starboard Value LP, (viii) Starboard Value GP LLC, (ix) Starboard Principal Co LP, (x) Starboard Principal Co GP LLC, (xi) Starboard Value R GP LLC, (xii) Starboard X Master Fund Ltd, (xiii) Jeffrey C. Smith, (xiv) Peter A. Feld, and (xv) any Starboard managed affiliate or Starboard managed account that may join the Starboard Schedule 13D group following the date of this Amendment.