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                                                                     EXHIBIT 4.2


                                 AMENDMENT NO. 1


                                       TO


                        PREFERRED STOCK RIGHTS AGREEMENT

        This Amendment No. 1 to Preferred Stock Rights Agreement (this
"Amendment") is dated as of November 6, 2001 between Critical Path, Inc. (the
"Company"), and Computershare Trust Company, Inc. (the "Rights Agent"), with
reference to the following:

        A. The Company and the Rights Agent entered into that certain Preferred
Stock Rights Agreement dated as of March 19, 2001 (the "Agreement") in order to
implement a shareholder rights plan as more fully described therein.

        B. The Company desires to amend the Agreement in certain respects in
order to permit certain investors to purchase securities being offered by the
Company without causing such investors to become Acquiring Persons (as defined
in the Agreement) and thereby trigger the occurrence of a Distribution Date (as
defined in the Agreement).

        C. Under the Agreement, the Company and the Rights Agent may amend the
Agreement, at any time prior to a Distribution Date, which has yet to occur.

        NOW, THEREFORE, pursuant to Section 27 of the Agreement, the Company and
the Rights Agent hereby amend, effective upon the date hereof, the definition of
the term "Acquiring Person" set forth in Section 1(a) of the Agreement to read
in its entirety as follows:

                "(a) "ACQUIRING PERSON" shall mean any Person, who or which,
together with all Affiliates and Associates of such Person, shall be the
Beneficial Owner of 15% or more of the Common Shares of the Company then
outstanding, but shall not include the Company, any Subsidiary of the Company or
any employee benefit plan of the Company or of any Subsidiary of the Company, or
any entity holding Common Shares for or pursuant to the terms of any such plan.
Notwithstanding the foregoing, no Person shall be deemed to be an Acquiring
Person as the result of an acquisition of Common Shares or Exchangeable Shares
by the Company which, by reducing the number of shares outstanding, increases
the proportionate number of shares beneficially owned by such Person to 15% or
more of the Common Shares of the Company then outstanding; provided, however,
that if a Person shall become the Beneficial Owner of 15% or more of the Common
Shares of the Company then outstanding by reason of share purchases by the
Company and shall, after such share purchases by the Company, become the
Beneficial Owner of any additional Common Shares of the Company (other than
pursuant to a dividend or distribution paid or made by (i) the Company on the
outstanding Common Shares in Common Shares or pursuant to a split or subdivision
of the outstanding Common Shares or (ii) Exchangeco on the outstanding
Exchangeable Shares in Exchangeable Shares or pursuant to a split or subdivision
of the outstanding Exchangeable Shares), then such Person shall be deemed to be
an Acquiring Person unless upon becoming the Beneficial Owner of such additional


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Common Shares of the Company such Person does not beneficially own 15% or more
of the Common Shares of the Company then outstanding. Notwithstanding the
foregoing,

                (i) if the Company's Board of Directors determines in good faith
        that a Person who would otherwise be an "Acquiring Person," as defined
        pursuant to the foregoing provisions of this paragraph (a), has become
        such inadvertently (including, without limitation, because (A) such
        Person was unaware that it Beneficially Owned a percentage of the Common
        Shares of the Company that would otherwise cause such Person to be an
        "Acquiring Person," as defined pursuant to the foregoing provisions of
        this paragraph (a), or (B) such Person was aware of the extent of the
        Common Shares of the Company it Beneficially Owned but had no actual
        knowledge of the consequences of such Beneficial Ownership under this
        Agreement) and without any intention of changing or influencing control
        of the Company, and if such Person divested or divests as promptly as
        practicable a sufficient number of Common Shares so that such Person
        would no longer be an "Acquiring Person," as defined pursuant to the
        foregoing provisions of this paragraph (a), then such Person shall not
        be deemed to be or to have become an "Acquiring Person" for any purposes
        of this Agreement;

                (ii) if, as of the date of this Agreement, any Person is the
        Beneficial Owner of 15% or more of the Common Shares of the Company
        outstanding, such Person shall not be or become an "Acquiring Person,"
        as defined pursuant to the foregoing provisions of this paragraph (a),
        unless and until such time as such Person shall become the Beneficial
        Owner of additional Common Shares of the Company (other than pursuant to
        a dividend or distribution paid or made by (i) the Company on the
        outstanding Common Shares in Common Shares or pursuant to a split or
        subdivision of the outstanding Common Shares or (ii) Exchangeco on the
        outstanding Exchangeable Shares in Exchangeable Shares or pursuant to a
        split or subdivision of the outstanding Exchangeable Shares), unless,
        upon becoming the Beneficial Owner of such additional Common Shares of
        the Company, such Person is not then the Beneficial Owner of 15% or more
        of the Common Shares of the Company then outstanding; and

                (iii) the term "Acquiring Person" shall not mean:

                        A. General Atlantic Partners 74, L.P., a Delaware
                        limited partnership, GAP Coinvestment Partners II, L.P.,
                        a Delaware limited partnership, and GapStar, LLC, a
                        Delaware limited liability company (referred to
                        collectively with their respective Affiliates and
                        Associates as "GAP") so long as GAP does not increase
                        (other than an increase resulting solely from a
                        reduction of the number of shares of outstanding Common
                        Stock, including by reason of purchases of Common Stock
                        or Exchangeable Shares by the Company) its Beneficial
                        Ownership of Common Stock to a percentage of the
                        outstanding shares of Common Stock that is greater than:
                        (1) the percentage of the outstanding shares of Common
                        Stock represented by the sum of (x) the shares as to
                        which GAP has Beneficial Ownership as of the close of
                        business on November 7, 2001 (if any), excluding, for
                        purposes of this calculation, any Common Stock which GAP
                        Beneficially Owns by reason of its holdings of the GAP
                        Sub Notes




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                        (as defined in that certain Stock and Warrant Purchase
                        and Exchange Agreement (the "Purchase Agreement") dated
                        November 8, 2001 by and among the Company and the
                        "Purchasers" named therein), plus (y) the shares as to
                        which GAP obtains Beneficial Ownership pursuant to the
                        consummation of the transactions described in the
                        Purchase Agreement, calculated assuming the Warrants (as
                        defined in the Purchase Agreement) are immediately
                        exercisable; or (2) such lesser percentage as to which
                        GAP has Beneficial Ownership following any transfer of
                        securities by GAP after consummation of the transactions
                        described in the Purchase Agreement (except that this
                        clause A. shall pertain only until such time as GAP has
                        Beneficial Ownership of less than fifteen percent (15%)
                        of the outstanding shares of Common Stock); provided,
                        that any shares of Common Stock Beneficially Owned by
                        one or more officers or directors of the Company where
                        (x) such officers or directors are also included within
                        the term "GAP" and (y) such shares of Common Stock were
                        distributed directly by the Company to such officers or
                        directors as equity based compensation, shall be
                        excluded from the calculation of the Beneficial
                        Ownership of GAP for purposes of the definition of
                        "Acquiring Person" if the inclusion of such shares of
                        Common Stock in such calculation, by itself, would
                        otherwise cause GAP to be an Acquiring Person;

                        B. Vectis CP Holdings, LLC (referred to collectively
                        with its Affiliates and Associates as "Vectis") so long
                        as Vectis does not increase (other than an increase
                        resulting solely from a reduction of the number of
                        shares of outstanding Common Stock, including by reason
                        of purchases of Common Stock or Exchangeable Shares by
                        the Company) its Beneficial Ownership of Common Stock to
                        a percentage of the outstanding shares of Common Stock
                        that is greater than: (1) the percentage of the
                        outstanding shares of Common Stock represented by the
                        sum of (x) the shares as to which Vectis has Beneficial
                        Ownership as of the close of business on November 7,
                        2001 (if any), plus (y) the shares as to which Vectis
                        obtains Beneficial Ownership pursuant to the
                        consummation of the transactions described in the
                        Purchase Agreement; or (2) such lesser percentage as to
                        which Vectis has Beneficial Ownership following any
                        transfer of securities by Vectis after consummation of
                        the transactions described in the Purchase Agreement
                        (except that this clause B. shall pertain only until
                        such time as Vectis has Beneficial Ownership of less
                        than fifteen percent (15%) of the outstanding shares of
                        Common Stock); provided, that any shares of Common Stock
                        Beneficially Owned by one or more officers or directors
                        of the Company where (x) such officers or directors are
                        also included within the term "Vectis" and (y) such
                        shares of Common Stock were distributed directly by the
                        Company to such officers or directors as equity based
                        compensation, shall be excluded from the calculation of
                        the Beneficial Ownership of Vectis for purposes of the
                        definition of "Acquiring Person" if the inclusion of
                        such shares of Common Stock in




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                        such calculation, by itself, would otherwise cause
                        Vectis to be an Acquiring Person; and

                        C. Cenwell Limited and Campina Enterprises Limited
                        (referred to collectively with their respective
                        Affiliates and Associates as "Cenwell") so long as
                        Cenwell does not increase (other than an increase
                        resulting solely from a reduction of the number of
                        shares of outstanding Common Stock, including by reason
                        of purchases of Common Stock or Exchangeable Shares by
                        the Company) its Beneficial Ownership of Common Stock to
                        a percentage of the outstanding shares of Common Stock
                        that is greater than: (1) the percentage of the
                        outstanding shares of Common Stock represented by the
                        sum of (x) the shares as to which Cenwell has Beneficial
                        Ownership as of the close of business on November 7,
                        2001 (if any), plus (y) the shares as to which Cenwell
                        obtains Beneficial Ownership pursuant to the
                        consummation of the transactions described in the
                        Purchase Agreement; or (2) such lesser percentage as to
                        which Cenwell has Beneficial Ownership following any
                        transfer of securities by Cenwell after consummation of
                        the transactions described in the Purchase Agreement
                        (except that this clause C. shall pertain only until
                        such time as Cenwell has Beneficial Ownership of less
                        than fifteen percent (15%) of the outstanding shares of
                        Common Stock)."

        The undersigned officer of the Company, being an appropriate officer of
the Company and authorized to do so by resolution of the board of directors of
the Company passed at a meeting duly held thereby, hereby certifies to the
Rights Agent that this Amendment is in compliance with the terms of Section 27
of the Agreement.

        This Amendment may be executed in any number of counterparts, each of
which shall be deemed an original, and all of this together shall constitute one
instrument.




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         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed as of the day and year first above written.



                                  CRITICAL PATH, INC.


                                  By: /s/ MICHAEL ZUKERMAN
                                     ------------------------------------
                                  Name: Michael Zukerman
                                  Title: Senior Vice President



                                  COMPUTERSHARE TRUST COMPANY, INC.


                                  By: /s/ KELLIE GWINN
                                     ------------------------------------
                                  Name: Kellie Gwinn
                                  Title: Vice President

                                  COMPUTERSHARE TRUST COMPANY, INC.


                                  By: /s/LAURA SISNEROS
                                     ------------------------------------
                                  Name: Laura Sisneros
                                  Title: Vice President


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