Exhibit 10.1

LIMITED GUARANTEE

Limited Guarantee, dated as of July 7, 2009 (this “Limited Guarantee”), by each
of STG III, L.P., a Delaware limited partnership (“STG III”), and STG III-A,
L.P., a Delaware limited partnership (“STG III-A” and, together with STG III,
the “Guarantors”), in favor of MSC.Software Corporation (the “Guaranteed
Party”).

1. Limited Guarantee. To induce the Guaranteed Party to enter into an Agreement
and Plan of Merger, dated as of July 7, 2009 (as it may be amended from time to
time, the “Merger Agreement”; capitalized terms used but not defined herein
shall have the meanings given to such terms in the Merger Agreement), by and
among Maximus Holdings Inc., a Delaware corporation (“Parent”), Maximus Inc., a
Delaware corporation and wholly-owned subsidiary of Parent (“Merger Sub”), and
the Guaranteed Party, pursuant to which Merger Sub, or a permitted assignee,
will merge with and into the Guaranteed Party, each of the Guarantors, severally
and not jointly (based on their respective Pro Rata Portions (as defined
below)), hereby absolutely, unconditionally and irrevocably guarantees to the
Guaranteed Party the due and punctual performance and discharge of the payment
obligations of Parent under Sections 11.04(c) and 11.04(d) of the Merger
Agreement (the “Obligations”). The “Pro Rata Portion” for STG III shall be
88.29%, and the “Pro Rata Portion” for STG III-A shall be 11.71%. The
obligations of each Guarantor hereunder are those of primary obligor, and not
merely as surety, and are independent of the Obligations and the obligations of
any other guarantor, and a separate action may be brought against the Guarantor
to enforce this Limited Guaranty whether or not the Guaranteed Party or any
other person or entity is joined as a party.

2. Nature of Guarantee. The Guaranteed Party shall not be obligated to file any
claim relating to the Obligations in the event that Parent or Merger Sub becomes
subject to a bankruptcy, reorganization or similar proceeding, and the failure
of the Guaranteed Party to so file shall not affect the Guarantors’ obligations
hereunder. In the event that any payment to the Guaranteed Party in respect of
the Obligations is rescinded or must otherwise be returned for any reason
whatsoever, the Guarantors shall remain liable hereunder with respect to the
Obligations as if such payment had not been made. This is an unconditional
guarantee of payment and not merely of collectibility.

3. Changes in Obligations; Certain Waivers. Each of the Guarantors agrees that
the Guaranteed Party may at any time and from time to time, without notice to or
further consent of such Guarantor, extend the time of payment of any of the
Obligations, and may also make any agreement with Parent, Merger Sub or any
assignee of Parent or Merger Sub pursuant to Section 11.06(b) of the Merger
Agreement (“Assignee”), for the extension, renewal, payment, compromise,
discharge or release thereof, in whole or in part, or for any modification of
the terms thereof or of any other agreement between the Guaranteed Party and
Parent, Merger Sub or any Assignee without in any way impairing or affecting
such Guarantor’s obligations under this Limited Guarantee, but in any case
subject to the last sentence of Section 4(a) and to Section 7(a). Each Guarantor
agrees that, except as set forth in Section 7(a), the obligations of such
Guarantor hereunder shall not be released or discharged, in whole or in part, or
otherwise affected by (a) the failure of the Guaranteed Party to assert any
claim or demand or to enforce any right or remedy

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against Parent, Merger Sub or any Assignee; (b) any change in the time, place or
manner of payment of any of the Obligations or any rescission, waiver,
compromise, consolidation or other amendment or modification of any of the terms
or provisions of the Merger Agreement or any other agreement evidencing,
securing or otherwise executed in connection with any of the Obligations;
(c) any change in the corporate existence, structure or ownership of Parent,
Merger Sub or any Assignee; (d) any insolvency, bankruptcy, reorganization or
other similar proceeding affecting Parent, Merger Sub or any Assignee; (e) the
existence of any claim, set-off or other right which such Guarantor may have at
any time against Parent, Merger Sub, any Assignee or the Guaranteed Party,
whether in connection with the Obligations or otherwise; or (f) the adequacy of
any other means the Guaranteed Party may have of obtaining repayment of any of
the Obligations. To the fullest extent permitted by law, each Guarantor hereby
expressly waives any and all rights or defenses arising by reason of any law
which would otherwise require any election of remedies by the Guaranteed Party.
Each Guarantor waives promptness, diligence, notice of the acceptance of this
Limited Guarantee and of the Obligations, presentment, demand for payment,
notice of non-performance, default, dishonor and protest, notice of any
Obligations incurred and all other notices of any kind (except for notices to be
provided to Parent, Merger Sub and Shearman & Sterling LLP in accordance with
Section 11.01 of the Merger Agreement), all defenses which may be available by
virtue of any valuation, stay, moratorium law or other similar law now or
hereafter in effect, any right to require the marshalling of assets of Parent,
Merger Sub or any Assignee, and all suretyship defenses generally (other than
fraud or willful misconduct by the Guaranteed Party or any of its Subsidiaries,
defenses to the payment of the Obligations that are available to Parent or
Merger Sub under the Merger Agreement or breach by the Guaranteed Party of this
Limited Guarantee). Each Guarantor acknowledges that it will receive substantial
direct and indirect benefits from the transactions contemplated by the Merger
Agreement and that the waivers set forth in this Limited Guarantee are knowingly
made in contemplation of such benefits.

4. Additional Agreements.

a) The Guaranteed Party hereby covenants and agrees that it shall not institute,
and shall cause its Affiliates not to institute, any proceeding or bring any
other claim arising under, or in connection with, the Merger Agreement or the
transactions contemplated thereby or otherwise relating thereto against the
Guarantors (except for claims against the Guarantors under this Limited
Guarantee, subject to the limitations described herein), Parent or Merger Sub or
against (a) any of the Guarantors’ respective former, current or future
directors, officers, agents, Affiliates (other than Parent or Merger Sub) or
employees, (b) any of the respective former, current or future general or
limited partners, members, managers or stockholders of the Guarantors or any
Affiliate thereof (other than Parent or Merger Sub), or (c) any former, current
or future directors, officers, agents, Affiliates, general or limited partners,
members, managers or stockholders of any of the foregoing (other than Parent or
Merger Sub) ((a) through (c) collectively, the “Guarantor Affiliates”).
Notwithstanding the foregoing, in connection with the pursuit by the Guaranteed
Party of a claim under this Limited Guarantee, the Guaranteed Party may pursue a
declaratory judgment claim against Parent to demonstrate that Parent has failed
to perform its obligations under Sections 11.04(c) and 11.04(d) of the Merger
Agreement; provided that such claim does not seek any other remedy (including
damages) against Parent or Merger Sub. Notwithstanding anything to the contrary
contained in this Limited Guarantee, the Guaranteed Party hereby agrees that to
the extent Parent is relieved of its obligations under Sections 11.04(c) and
11.04(d) of the Merger Agreement, each of the Guarantors shall be similarly
relieved of its obligations under this Limited Guarantee.

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b) Each of the Guarantors hereby covenants and agrees that it shall not
institute, and shall cause its Affiliates not to institute, any proceedings
asserting that this Limited Guarantee is illegal, invalid or unenforceable in
accordance with its terms, subject to the effects of bankruptcy, insolvency,
fraudulent conveyance, reorganization, moratorium or other similar laws
affecting creditors’ rights generally, and general equitable principles (whether
considered in a proceeding in equity or at law). Each of the Guarantors hereby
unconditionally and irrevocably agrees not to exercise any rights that it may
now have or hereafter acquire against Parent, Merger Sub or any Assignee that
arise from the existence, payment, performance, or enforcement of such
Guarantor’s obligations under or in respect of this Limited Guarantee or any
other agreement in connection therewith, including, without limitation, any
right of subrogation, reimbursement, exoneration, contribution or
indemnification and any right to participate in any claim or remedy of the
Guaranteed Party against Parent, Merger Sub or any Assignee, whether or not such
claim, remedy or right arises in equity or under contract, statute or common
law, including, without limitation, the right to take or receive from Parent,
Merger Sub or any Assignee, directly or indirectly, in cash or other property or
by set-off or in any other manner, payment or security on account of such claim,
remedy or right, unless and until all of such Guarantor’s Obligations shall have
been paid in full in cash. If any amount shall be paid to a Guarantor in
violation of the immediately preceding sentence at any time prior to the payment
in full in cash of such Guarantor’s Obligations, such amount shall be received
and held in trust for the benefit of the Guaranteed Party and shall forthwith be
paid or delivered to the Guaranteed Party in the same form as so received (with
any necessary endorsement or assignment) to be credited and applied to such
Obligations, in accordance with the terms of the Merger Agreement, whether
matured or unmatured, or to be held as collateral for any such Obligations.

5. No Waiver; Cumulative Rights. No failure on the part of the Guaranteed Party
to exercise, and no delay in exercising, any right, remedy or power hereunder
shall operate as a waiver thereof, nor shall any single or partial exercise by
the Guaranteed Party of any right, remedy or power hereunder preclude any other
or future exercise of any right, remedy or power hereunder. Each and every
right, remedy and power hereby granted to the Guaranteed Party or allowed it by
law or other agreement shall be cumulative and not exclusive of any other, and
may be exercised by the Guaranteed Party at any time or from time to time.

6. Representations and Warranties. Each of the Guarantors, severally and not
jointly, hereby represents and warrants that:

a) the execution, delivery and performance of this Limited Guarantee have been
duly authorized by all necessary action and do not contravene any provision of
such Guarantor’s partnership agreement or other organizational documents or any
law, regulation, rule, decree, order, judgment or contractual restriction
binding on such Guarantor or its assets;

b) all consents, approvals, authorizations, permits of, filings with and
notifications to, any governmental authority necessary for the due execution,
delivery and performance of this Limited Guarantee by such Guarantor have been
obtained or made and all conditions thereof have been duly complied with, and no
other action by, and no notice to or filing with, any governmental authority or
regulatory body is required in connection with the execution, delivery or
performance of this Limited Guarantee;

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c) this Limited Guarantee constitutes a legal, valid and binding obligation of
such Guarantor enforceable against such Guarantor in accordance with its terms,
subject to (i) the effects of bankruptcy, insolvency, fraudulent conveyance,
reorganization, moratorium or other similar laws affecting creditors’ rights
generally, and (ii) general equitable principles (whether considered in a
proceeding in equity or at law); and

d) such Guarantor has available sufficient capital commitments from its limited
partners to pay and perform its Obligations under this Limited Guarantee, and
will have available sufficient capital commitments from its limited partners to
pay and perform such Obligations for so long as this Limited Guarantee shall
remain in effect in accordance with Section 7 hereof.

7. Continuing Guarantee; Enforcement. This Limited Guarantee shall remain in
full force and effect and shall be binding on each of the Guarantors and its
respective successors and assigns until the Obligations are satisfied in full.
Notwithstanding the foregoing, this Limited Guarantee shall terminate and the
Guarantors shall have no further obligations under this Limited Guarantee as of
the earliest of (i) the Effective Time, (ii) the termination of the Merger
Agreement in accordance with its terms (except a termination pursuant to which
Parent is obligated to make a payment pursuant to Section 11.04(c) thereof) and
(iii) 180 days after any termination of the Merger Agreement in accordance with
its terms under circumstances in which Parent would be obligated to make any
payment under Section 11.04(c) if the Guaranteed Party has not presented a claim
for payment of any Obligation to Parent and Merger Sub or the Guarantor by the
end of such 180 day period. Notwithstanding the foregoing, in the event that the
Guaranteed Party or any of its Affiliates asserts in any litigation or other
proceeding that (A) the provisions of Section 1 hereof limiting the Guarantors’
liability, the provisions of this Section 7, the provisions of Section 8 or
Section 9 hereof or (B) the provisions of Section 11.04(e), 11.04(f) or 11.04(g)
of the Merger Agreement limiting the liability of the Parent Related Parties are
illegal, invalid or unenforceable in whole or in part, or asserting any theory
of liability against the Guarantors, Parent, Merger Sub or any other Guarantor
Affiliate with respect to the transactions contemplated by the Merger Agreement
other than liability of the Guarantors under this Limited Guarantee (as limited
by the provisions of Section 1), then (i) the obligations of the Guarantors
under this Limited Guarantee shall terminate ab initio and be null and void,
(ii) if the Guarantors have previously made any payments under this Limited
Guarantee, they shall be entitled to recover such payments, and (iii) neither
the Guarantors, Parent, Merger Sub or any Guarantor Affiliate shall have any
liability to the Guaranteed Party with respect to the transactions contemplated
by the Merger Agreement or under this Limited Guarantee; provided, however that
if any Guarantor or any of its respective Affiliates shall institute any
proceedings asserting that this Limited Guarantee is illegal, invalid or
unenforceable in accordance with its terms, then, to the extent the Guaranteed
Party prevails in such litigation or proceeding, such Guarantor shall pay on
demand all reasonable fees and out-of-pocket expenses of the Guaranteed Party in
connection with such litigation or proceeding.

8. No Recourse. The Guaranteed Party by its acceptance of the benefits hereof,
covenants, agrees and acknowledges that no Person other than the Guarantors
shall have any obligation hereunder and that no recourse hereunder or under any
documents or instruments

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delivered in connection herewith shall be had against Parent, Merger Sub or any
Guarantor Affiliate, whether by the enforcement of any assessment or by any
legal or equitable proceeding, or by virtue of any statute, regulation or other
applicable law. The Guaranteed Party acknowledges and agrees that Parent and
Merger Sub have no assets and that no funds are expected to be contributed to
Parent or Merger Sub unless the Closing occurs. The Guaranteed Party further
agrees that neither it nor any of its Affiliates have any right of recovery
against the Guarantors, Parent, Merger Sub or any Guarantor Affiliate, through
Parent or Merger Sub or otherwise, whether by piercing of the corporate veil, by
a claim on behalf of Parent or Merger Sub against the Guarantors or Parent’s
stockholders or Affiliates, or otherwise, except for the rights under this
Limited Guarantee. Recourse against the Guarantors under this Limited Guarantee
shall be the exclusive remedy of the Guaranteed Party and its Affiliates against
the Guarantors, Parent, Merger Sub and any Guarantor Affiliate in respect of any
liabilities or obligations arising under, or in connection with, the Merger
Agreement or the transactions contemplated thereby. The Guaranteed Party hereby
covenants and agrees that it shall not institute, and it shall cause its
Affiliates not to institute, any proceeding or bring any other claim arising
under, or in connection with, the Merger Agreement or the transactions
contemplated thereby, against the Guarantors, Parent, Merger Sub or any
Guarantor Affiliate (except for claims against the Guarantors under this Limited
Guarantee, subject to the limitations described herein). Except as contemplated
under Section 10, nothing set forth in this Limited Guarantee shall affect or be
construed to confer or give any Person other than the Guarantors and the
Guaranteed Party (including any Person acting in a representative capacity) any
rights or remedies against any Person.

9. Release. By its acceptance of this Limited Guarantee, the Guaranteed Party
hereby covenants and agrees that (1) neither the Guaranteed Party nor any of its
Subsidiaries or Affiliates, and the Guaranteed Party agrees to the maximum
extent permitted by law, none of its officers, directors, security holders or
representatives, has or shall have any right of recovery under or in connection
with the Merger Agreement, or the transactions contemplated thereby or otherwise
relating thereto, and to the extent that it has or obtains any such right it, to
the maximum extent permitted by law, hereby waives (on its own behalf and on
behalf of each of the aforementioned Persons) each and every such right against,
and hereby releases, the Guarantors, Parent, Merger Sub and each Guarantor
Affiliate from and with respect to any claim, known or unknown, now existing or
hereafter arising, in connection with any transaction contemplated by or
otherwise relating to the Merger Agreement or the transactions contemplated
thereby, whether by or through attempted piercing of the corporate (or limited
liability company) veil, by or through a claim by or on behalf of Parent or
Merger Sub or any other Person against any Guarantors, or otherwise under any
theory of law or equity, other than claims against the Guarantors pursuant to
this Limited Guarantee (subject to the limitations described herein); and
(2) recourse against the Guarantors under this Limited Guarantee (and subject to
the limitations described herein) shall be the sole and exclusive remedy of the
Guaranteed Party. The Guaranteed Party acknowledges the Guarantor is agreeing to
enter into this Limited Guarantee in reliance on the provisions set forth in
Section 4(a) and this Section 9. This Section 9 shall survive termination of the
Limited Guarantee.

10. No Assignment. Neither of the Guarantors nor the Guaranteed Party may assign
its rights, interests or obligations hereunder to any other Person (except by
operation of law) without the prior written consent of the Guaranteed Party (in
the case of an assignment by either

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Guarantor) or the Guarantors (in the case of an assignment by the Guaranteed
Party); provided, however, the Guarantors may assign all or a portion of its
rights and obligations hereunder to an Affiliate capable of making the
representation set forth in Section 6(d) above or to an entity managed or
advised by an Affiliate of the Guarantors capable of making the representation
set forth in Section 6(d) above; provided further that no such assignment shall
relieve the Guarantors of any liability or obligation hereunder, except to the
extent actually performed or satisfied by the assignee.

11. Notices. All notices, requests and other communications to any party
hereunder shall be in writing and shall be deemed given if delivered personally,
facsimiled (which is confirmed) or sent by overnight courier (providing proof of
delivery) to the parties at the following addresses:

if to the Guaranteed Party, to it at:

MSC.Software Corporation

2 MacArthur Place

Santa Ana, CA 92707

Attention: General Counsel

Facsimile: (714) 784-4231

with a copy (which shall not constitute notice) to:

Davis Polk & Wardwell LLP

1600 El Camino Real

Menlo Park, CA 94025

Attention: Alan F. Denenberg

Facsimile: (650) 750-2111

if to the Guarantors, to them at:

STG III, L.P. and STG III-A, L.P.

c/o Symphony Technology Group

2475 Hanover Street

Palo Alto, CA 94304

Attention: Chief Financial Officer

Facsimile No.: (415) 358-8835

with a copy (which shall not constitute notice) to:

Shearman & Sterling LLP

525 Market Street

San Francisco, CA 94105

Attention: Steve L. Camahort

Facsimile No.: 415-616-1440

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or such other address or facsimile number as such party may hereafter specify by
like notice to the other parties hereto. All such notices, requests and other
communications shall be deemed received on the date of receipt by the recipient
thereof if received prior to 5:00 P.M. in the place of receipt and such day is a
business day in the place of receipt. Otherwise, any such notice, request or
communication shall be deemed not to have been received until the next
succeeding business day in the place of receipt.

12. Governing Law. This Limited Guarantee shall be governed by, and construed in
accordance with, the laws of the State of Delaware applicable to contracts
executed in and to be performed entirely within that State.

13. Consent to Jurisdiction. All actions and proceedings arising out of or
relating to this Limited Guarantee or any of the transactions contemplated
hereby shall be heard and determined in the Delaware Court of Chancery or, if
subject matter jurisdiction in the such court is not available, in the United
States District Court for the District of Delaware, and the parties hereto
hereby irrevocably submit to the exclusive jurisdiction of such courts (and, in
the case of appeals, appropriate appellate courts therefrom) in any such action
or proceeding and irrevocably waive the defense of an inconvenient forum to the
maintenance of any such action or proceeding. The consent to jurisdiction set
forth in this paragraph shall not constitute general consent to service of
process in the State of Delaware and shall have no effect for any purpose except
as provided in this paragraph and shall not be deemed to confer rights on any
Person other than the parties hereto. The parties hereto agree that a final
judgment in any such action or proceeding shall be conclusive and may be
enforced in other jurisdictions by suit on the judgment or in any other manner
provided by applicable law.

14. Waiver of Jury Trial. EACH PARTY ACKNOWLEDGES AND AGREES THAT ANY
CONTROVERSY WHICH MAY ARISE UNDER THIS LIMITED GUARANTEE IS LIKELY TO INVOLVE
COMPLICATED AND DIFFICULT ISSUES AND, THEREFORE, EACH SUCH PARTY IRREVOCABLY AND
UNCONDITIONALLY WAIVES ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN RESPECT OF
ANY LEGAL ACTION, SUIT OR PROCEEDING ARISING OUT OF OR RELATING TO THIS LIMITED
GUARANTEE OR THE TRANSACTIONS CONTEMPLATED HEREBY (EACH, A “PROCEEDING”). Each
party to this Limited Guarantee certifies and acknowledges that (a) no
Representative of any other party has represented, expressly or otherwise, that
such other party would not seek to enforce the foregoing waiver in the event of
a Proceeding, (b) such party has considered the implications of this waiver,
(c) such party makes this waiver voluntarily, and (d) such party has been
induced to enter into this Limited Guarantee by, among other things, the mutual
waivers and certifications in this Section 14.

15. Counterparts. This Limited Guarantee may be executed in counterparts (each
of which shall be deemed to be an original but all of which taken together shall
constitute one and the same agreement) and shall become effective when one or
more counterparts have been signed by each of the parties and delivered to the
other parties. The exchange of copies of this Limited Guarantee and of signature
pages by facsimile or electronic transmission shall constitute effective
execution and delivery of this Limited Guarantee as to the parties and may be
used in lieu of the original Limited Guarantee for all purposes. Signatures of
the parties transmitted by facsimile or electronic transmission shall be deemed
to be their original signatures for all purposes.

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16. Amendments. This Limited Guarantee may not be modified, amended, altered or
supplemented, except upon the execution and delivery of a written agreement
executed by each of the parties hereto.

17. Severability. If any term or other provision of this Limited Guarantee is
determined by a court of competent jurisdiction to be invalid, illegal or
incapable of being enforced by any rule of law or public policy, all other
terms, provisions and conditions of this Limited Guarantee shall nevertheless
remain in full force and effect. Upon such determination that any term or other
provision is invalid, illegal or incapable of being enforced, the parties hereto
shall negotiate in good faith to modify this Limited Guarantee so as to effect
the original intent of the parties as closely as possible to the fullest extent
permitted by applicable law in an acceptable manner to the end that the
transactions contemplated hereby are fulfilled to the extent possible.

[Remainder of page intentionally left blank]

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IN WITNESS WHEREOF, each of the undersigned has caused this Limited Guarantee to
be executed and delivered as of the date first written above by its officer
thereunto duly authorized.

 

STG III, L.P. and STG III-A, L.P. Each By:   STG III GP, L.P., its General
Partner By:   STG UGP, LLC, its General Partner By:  

/s/    William F. Chisholm

  Name: William F. Chisholm   Title: Managing Director

IN WITNESS WHEREOF, the Guaranteed Party has caused this Limited Guarantee to be
executed and delivered as of the date first written above by its officer
thereunto duly authorized.

 

MSC.SOFTWARE CORPORATION By:  

/s/    Ashfaq A. Munshi

Name:   Ashfaq A. Munshi Title:   Interim Chief Executive Officer and President

[Signature Page to Limited Guarantee]