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                                                                   EXHIBIT 10.18

                              CONSULTING AGREEMENT

        This Agreement is made as of August 16, 2001, by and between Laureen
DeBuono, an individual, located at __________, San Francisco, California ____
("Consultant") and Critical Path, Inc., a company located at 532 Folsom Street,
San Francisco, CA 94105 ("Critical Path").

        1. Engagement of Consultant; Consulting Tasks. Critical Path hereby
engages Consultant, and Consultant hereby agrees, to advise Critical Path on the
following matters, achieve the following objective or deliver the following work
product ("consulting tasks"):

                To lead the Critical Path Finance organization, on an interim
basis, as "Interim CFO", which includes responsibility for financial accounting
and reporting, financial planning, budgeting and analysis, investor relations,
treasury and tax, risk management, travel and facilities. Consultant shall
report directly to the CEO or Interim COO if the former has not been hired, and
shall also have direct and unfettered access to the Board of Directors and its
Audit Committee. Consultant shall be an interim member of the executive
management team, attend executive staff meetings, and participate in the
selection of the new CEO of Critical Path. Consultant shall also lead an
assessment of the Finance team and shall make staffing/hiring decisions
appropriate to the needs of the organization.

                Critical Path understands that the manner and means used by
Consultant to accomplish the consulting tasks is in the sole discretion and
control of Consultant. However, Consultant will utilize the highest degree of
skill and expertise in order to professionally accomplish the consulting tasks
in a timely fashion. It is also noted and agreed to by Critical Path that
Consultant is rendering no legal advice in the performance of her tasks
hereunder.

        2. Term. Consultant shall commence work under this Agreement on
September 5, 2001. The term of this Agreement shall be for a period of six (6)
months through February 29, 2002, unless terminated under the provisions of
Section 9, or extended upon mutual agreement of the parties.

        3. Time Commitment. Except where the nature of the consulting tasks
requires that they be performed at specific times, Consultant is free to choose
the specific times at which work will be performed. However, Consultant and
Critical Path agree that the work performed shall be on a four (4) day per week
basis (Monday through Thursday) through October 1, 2001, and thereafter on a
five (5) day per week basis through February 29, 2002. The work shall be
performed at the Critical Path facilities in San Francisco, with travel on
behalf of Critical Path when needed. Critical Path acknowledges that Consultant
is finishing tasks for other clients during the month of September and, as such,
understands that Consultant will be unavailable to work on Critical Path
projects from Friday through Sunday during this period, including September 24
through 26. Consultant agrees that she shall not take on any new consulting
assignments during the Term of this Agreement. Critical Path also acknowledges
that Consultant shall be unavailable November 20 through 25, 2001, December 24
through January 3, 2002, and February 15 through 24, 2002.

        4. Fees and Expenses. Consultant shall be paid $310,000 for the six (6)
month period ("Term"), which equates to $52,000 per month payable on the 1st of
each month, with the first such payment due on September 5, 2001. Consultant
shall also be reimbursed for business and business-related travel expenses
through the submission of itemized expense reports, and such expenses will be
payable within seven (7) days of submission of such reports. In addition,
Consultant shall be granted, on September 5, 2001, at the market price on that
date, an option to purchase 200,000 shares of Critical Path stock, of which
33,333 options shall fully vest on a monthly basis, beginning on September 5,
2001 and thereafter on the 1st of each month. In addition, during the Term of
the Agreement, in the event other executive officers receive stock options as a
result of a financing, stock split, annual option grant program or other similar
event, then Consultant will receive additional stock options on a "proportional
basis". During the Term of the Agreement, Consultant will be subject to all of
the restrictions imposed on executive officers with regard to trading in
Critical Path stock. After the Term of the Agreement, there will be no such
restrictions imposed on Consultant.

        5. Travel. Upon reasonable request by Critical Path, Consultant shall
travel to appropriate locations to perform the consulting tasks (where the
nature of such tasks so requires) within the Time Commitment noted in Point 3
above. Travel time shall count as time spent on the consulting tasks.

        6. No Conflicts. Consultant represents and warrants that: (a) Consultant
is not bound by, and will not enter into, any oral or written agreement with
another party that conflicts in any way with Consultant's obligations under

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this Agreement or any agreement made or to be made in connection herewith and
(b) Consultant's agreements and performance under this Agreement and such
related agreements do not require consent or approval of any person that has not
already been obtained.

        7. Confidentiality of Protected Information.

                (a)     Definition. "Protected Information" consists of:

                        (i)     information that Critical Path considers to be
                                proprietary and/or confidential and which was
                                previously or is hereafter disclosed or made
                                available to Consultant by Critical Path
                                including information relating to Critical Path
                                or its business that becomes available to
                                Consultant due to Consultant's access to
                                Critical Path's property or products; and

                        (ii)    information that has been or is created,
                                developed, conceived, reduced to practice or
                                discovered by Consultant (alone or jointly with
                                others) using any Protected Information or any
                                property or materials supplied to Consultant by
                                Critical Path; and

                        (iii)   information that was or is created, conceived,
                                reduced to practice, discovered, developed by,
                                or made known to, Consultant (either alone or
                                jointly with others) during the period that
                                Consultant is retained as a Consultant by
                                Critical Path and which is within the scope of
                                the consulting tasks.

                        By way of illustration but not limitation, Protected
                        Information includes: inventions, discoveries,
                        developments, improvements, trade secrets, know-how,
                        ideas, techniques, designs, processes, formulae, data
                        and software (collectively, "Inventions"); plans for
                        research, development, new products, marketing and
                        selling; budgeting and financial information; production
                        and sales information including prices, costs,
                        quantities and information about suppliers and
                        customers; information about business relationships; and
                        information about skills and compensation of Critical
                        Path employees and consultants.

                (b)     Non-Disclosure; Restricted Use. At all times during and
                        after Consultant's engagement by Critical Path,
                        Consultant shall: hold Protected Information in
                        strictest confidence; not disclose Protected Information
                        to any third party without written consent of a Critical
                        Path officer; take all reasonable steps to safeguard
                        Protected Information; and not use Protected Information
                        for any purpose other than performing work for Critical
                        Path.

                (c)     Exclusions. This Section 7 shall impose no restrictions
                        on use and disclosure of any information which
                        Consultant can establish by legally sufficient evidence:
                        (i) was otherwise known to Consultant at the time of
                        disclosure; or (ii) becomes known or available to
                        Consultant without restriction from a third party
                        without violation of any confidentiality obligation to
                        Critical Path; or (iii) is or becomes part of the public
                        domain without violation of this Agreement by
                        Consultant.

                (d)     Third Party Information. The use and disclosure
                        restrictions in this Section 7 shall also apply to
                        proprietary or confidential information of a third party
                        received by Critical Path and disclosed to Consultant.

                (e)     Ownership. Critical Path shall be the sole owner of all
                        Protected Information. Consultant hereby assigns to
                        Critical Path any rights it may have or acquire in any
                        Protected Information, all patents issuing therefrom,
                        and all copyrights or any other rights existing therein.

        8. Consultant Not to Disclose Confidential Information of Consultant or
Others. Consultant shall not disclose any information to Critical Path which it
believes to be confidential or proprietary to itself or a third party.

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        9. Termination. This Agreement may be terminated by either party on
twenty (20) days' written notice to the other, regardless of whether or not the
consulting tasks have yet been completed. However, in the event Critical Path
terminates this Agreement prior to the end of the Term, for any reason
whatsoever, other than for a fraud or embezzlement perpetrated upon Critical
Path, then Critical Path shall provide to Consultant a "termination payment"
equal to two (2) months of consulting income, or $104,000, payable on the date
of termination. The obligation of Critical Path to pay fully on this Agreement
for consulting services rendered will not terminate and, as such, all amounts
owing to Consultant hereunder, including reimbursement of business and
business-related travel expenses, shall be paid to Consultant immediately upon
termination. On termination, Consultant shall deliver to Critical Path any
supplies or equipment provided by Critical Path for use in performing the
consulting tasks, and all physical property and documents or other media
(including copies) that contain Protected Information.

        10. Independent Contractor; No Employee Benefits. Consultant shall at
all times act as an independent contractor and not as an employee of Critical
Path. Accordingly, Consultant understands that Critical Path will not pay or
withhold from payments to Consultant under this Agreement any FICA (social
security), state unemployment or disability insurance premiums, state or federal
income taxes, or other taxes and that Consultant is responsible for paying his
or her own federal self-employment tax (in lieu of FICA), state and federal
income taxes (including estimated tax payments) and other applicable taxes.
Consultant also understands that he or she will receive no employee benefits of
any kind including, for example, health insurance.

        11. Miscellaneous. Neither party has any authority to bind the other in
any way. This Agreement and the Indemnification Agreement dated August 16, 2001
("Indemnification Agreement") by and between the parties hereto (by which
Critical Path fully indemnifies Consultant for any actions and expenses that may
arise from the action taken or advice rendered by the Consultant in the
performance of her duties hereunder), constitute the entire agreement between
the parties relating to the subject matter hereof. Except as expressly provided
herein, this Agreement and the Indemnification Agreement shall not be amended
except by written agreement between the parties. No oral waiver, amendment or
modification shall be effective under any circumstances. If any term, covenant
or condition of this Agreement shall for any reason be held unenforceable by a
court of competent jurisdiction, the rest of this Agreement shall remain in full
force and shall in no way be affected or impaired. The representations and
warranties herein shall survive termination or expiration of this Agreement.
This Agreement shall be governed and construed under California law, excluding
choice of law rules. In addition, Critical Path agrees to add Consultant's name
as a "named insured" on the current Critical Path D&O Policy (and any future
Critical Path D&O policies that may cover the Term of this Agreement), effective
September 5, 2001.

        12. Taxpayer Identification Number. The information in this Section is
provided in lieu of IRS Form W-9. Consultant's taxpayer identification number
is:

               (a)    Social Security Number: _________________
                      (For individuals or sole proprietorships).

                             OR

               (b)    Employer I.D. Number: __ __ - __ __ __ __ __ __ __
                      (For all other entities).

        IN WITNESS WHEREOF, the parties have caused this Agreement to be
executed as of the date set forth above.

CRITICAL PATH, INC.                         LAUREEN DEBUONO

By: /s/ William McGlashan                   By: /s/ Laureen DeBuono
   ---------------------------                  --------------------------------
                                                Laureen DeBuono

                                       3<PAGE>
                                                                   EXHIBIT 10.19

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NOTICE OF GRANT OF STOCK OPTIONS                CRITICAL PATH, INC.
AND OPTION AGREEMENT                            ID: 91-1788-300
                                                532 Folsom Street
                                                San Francisco, CA 94105

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LAUREEN DEBUONO                                 OPTION NUMBER:  004250
                                                PLAN:           1998
                                                ID:

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Effective 9/5/2001, you have been granted a(n) Non-Qualified Stock Option to buy
200,000 shares of Critical Path, Inc. (the Company) stock at $0.3400 per share.

The total option price of the shares granted is $68,000.00.

Shares in each period will become fully vested on the date shown.

                Shares       Vest Type       Full Vest       Expiration
                ------       ---------       ---------       ----------
                33,332     On Vest Date      9/5/2001         9/5/2011
               166,668          Monthly      2/4/2002         9/5/2011

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By your signature and the Company's signature below, you and the Company agree
that these options are granted under and governed by the terms and conditions of
the Company's Stock Option Plan as amended and the Option Agreement, all of
which are attached and made a part of this document.

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/s/ David Hayden
-----------------------------------             --------------------------------
Critical Path, Inc.                             Date

/s/ Laureen DeBuono
-----------------------------------             --------------------------------
Laureen DeBuono                                 Date

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