Rabbi Trust Agreement for MSC.Software Corporation 2005 Supplement Retirement and Deferred Compensation Plan TABLE OF CONTENTS

EXHIBIT 10.1

Rabbi Trust Agreement

for

MSC.Software Corporation

2005 Supplement Retirement and

Deferred Compensation Plan

TABLE OF CONTENTS

Rabbi Trust Agreement

This Agreement, made this 1st day of January, 2005, by and between MSC.Software Corporation (the “Company”) and its affiliates, and Wells Fargo Bank, N.A., (the “Trustee”),

WITNESSETH:

WHEREAS, Company has adopted a non-qualified deferred compensation Plan entitled MSC.Software Corporation 2005 Supplemental Retirement and Deferred Compensation Plan (the “Plan”);

WHEREAS, Company wishes to establish a trust (hereinafter called “Trust”) and to contribute to the Trust assets that shall be held therein, subject to the claims of Company’s Insolvency, as herein defined, until paid to Plan participants and their beneficiaries in such manner and at such times as specified in the Plan;

WHEREAS, it is the intention of the parties that this Trust shall constitute an unfunded arrangement and shall not affect the status of the Plan as an unfunded plan maintained for the purpose of providing deferred compensation for a select group of management or highly compensated employees for purposes of Title I of the Employee Retirement Income Security Act of 1974;

WHEREAS, it is the intention of Company to make contributions to the Trust to provide itself with a source of funds to assist it in the meeting of its liabilities under the Plan;

NOW, THEREFORE, the parties do hereby establish the Trust and agree that the Trust shall be comprised, held and disposed of as follows:

Section 1. Establishment of Trust.

(a) Company hereby deposits with Trustee in trust assets, which shall become the principal of the Trust to be held, administered and disposed of by Trustee as provided in this Trust Agreement.

(b) The Trust hereby established shall be irrevocable by Company.

(c) The Trust is intended to be a grantor trust, of which Company is the grantor, within the meaning of subpart E, part 1, subchapter J, chapter 1, subtitle A of the Internal Revenue Code of 1986, as amended, and shall be construed accordingly. However, the Trustee does not warrant and shall not be liable for any tax consequences associated with the Trust or participation in the Plan.

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(d) The principal of the Trust, and any earnings thereon shall be held separate and apart from other funds of Company and shall be used exclusively for the uses and purposes of Plan participants and general creditors as herein set forth. Plan participants and their beneficiaries shall have no preferred claim on, or any beneficial ownership interest in, any assets of the Trust. Any rights created under the Plan and this Trust Agreement shall be mere unsecured contractual rights of Plan participants and their beneficiaries against Company. Any assets held by the Trust will be subject to the claims of Company’s general creditors under federal and state law in the event of Insolvency, as defined in Section 3(a) herein.

(e) Company, in its sole discretion, may at any time, or from time to time, make additional deposits of cash or other property, acceptable to the Trustee, in trust with Trustee to augment the principal to be held, administered and disposed of by Trustee as provided in this Trust Agreement. Neither Trustee nor any Plan participant or beneficiary shall have any right to compel such additional deposits.

Section 2. Payments to Plan Participants and Their Beneficiaries.

(a) Company shall deliver to Trustee a schedule (the “Payment Schedule”) that indicates the amounts payable in respect of each Plan participant (and his or her beneficiaries), that provides a formula or other instructions acceptable to Trustee for determining the amounts so payable, the form in which such amount is to be paid (as provided for or available under the Plan, and the time of commencement for payment of such amounts. Except as otherwise provided herein, Trustee shall make payments to the Plan participants and their beneficiaries in accordance with such Payment Schedule. The Company shall make provision for the reporting and withholding of any Federal, state or local taxes that may be required to be withheld with respect to the payment of benefits pursuant to the terms of the Plan and shall pay amounts withheld to the appropriate taxing authorities. The Trustee may forward amounts to be withheld from the participants’ benefits to the Company for remittal to the appropriate taxing authorities. The Trustee shall have no responsibility or liability for determining and/or reporting any such taxes.

(b) The entitlement of a Plan participant or his or her beneficiaries to benefits under the Plan shall be determined by Company or such party as it shall designate under the Plan, and any claim for such benefits shall be considered and reviewed under the procedures set out in the Plan.

(c) Company may make payment of benefits directly to Plan participants or their beneficiaries as they become due under the terms of the Plan. Company shall notify Trustee of its decision to make payment of benefits directly prior to the time amounts are payable to participants or their beneficiaries. In addition, if the principal of the Trust, and any earnings thereon, are not sufficient to make payments of benefits in accordance with the terms of the Plan, Company shall make the balance of each such payment as it falls due. Trustee shall notify Company where principal and earnings are not sufficient. The trustee shall not be liable for the inadequacy of the Trust to pay all amounts due under the Plan, unless such inadequacy is the direct result of trustee’s willful misconduct, bad faith or negligence.

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Section 3. Trustee Responsibility Regarding Payments to Trust Beneficiary When Company is Insolvent.

(a) Trustee shall cease payment of benefits to Plan participants and their beneficiaries if the Company is Insolvent. Company shall be considered “Insolvent” for purposes of this Trust Agreement if (i) Company is unable to pay its debts as they become due, or (ii) Company is subject to a pending proceeding as a debtor under the United States Bankruptcy Code or any comparable state or federal regulatory law.

(b) At all times during the continuance of this Trust, as provided in Section 1(d) hereof, the principal and income of the Trust shall be subject to claims of general creditors of Company under federal and state law as set forth below.

(1) The Board of Directors and the Chief Executive Officer of Company shall have the duty to inform Trustee in writing of Company’s Insolvency. If a person claiming to be a creditor of Company alleges in writing to Trustee that Company has become Insolvent, Trustee shall determine whether Company is Insolvent and, pending such determination, Trustee shall discontinue payment of benefits to Plan participants or their beneficiaries. Except as stated above, the Trustee shall have no duty to determine whether the Company is Insolvent.

(2) Unless Trustee has actual knowledge of Company’s Insolvency, or has received notice from Company or a person claiming to be a creditor alleging that Company is Insolvent, Trustee shall have no duty to inquire whether Company is Insolvent. Trustee may in all events rely on such evidence concerning Company’s solvency as may be furnished to Trustee and that provides Trustee with a reasonable basis for making a determination concerning Company’s solvency.

(3) If at any time Trustee has determined that Company is Insolvent, Trustee shall discontinue payments to Plan participants or their beneficiaries and shall hold the assets of the Trust for the benefit of Company’s general creditors. Nothing in this Trust Agreement shall in any way diminish any rights of the Plan participants or their beneficiaries to pursue their rights as general creditors of Company with respect to benefits due under the Plan or otherwise.

(4) Trustee shall resume the payment of benefits to Plan participants or their beneficiaries in accordance with Section 2 of this Trust Agreement only after Trustee has determined that Company is not Insolvent (or is no longer Insolvent).

(c) Provided that there are sufficient assets, if Trustee discontinues the payment of benefits from the Trust pursuant to Section 3(b) hereof and subsequently resumes such payments, the first payment following such discontinuance shall include the aggregate amount of all payments due to Plan participants or their beneficiaries under the terms of the Plan for the period of such discontinuance, less the aggregate amount of any payments made to Plan participants or their beneficiaries by Company in lieu of the payments provided for hereunder during any such period of discontinuance.

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Section 4. Payments to Company.

Except as provided in Section 3 hereof, Company shall have no right or power to direct Trustee to return to Company or to divert to others any of the Trust assets before all payment of benefits have been made to Plan participants and their beneficiaries pursuant to the terms of the Plan.

Section 5. Investment Authority.

(a) The Company may from time to time issue directions to the Trustee instructing the Trustee how to invest the Trust. Prior to issuing any such directions, the Company shall certify to the Trustee the person(s) at the Company who have the authority to issue such directions. If such directions are issued, the Trustee shall have no fiduciary responsibility or liability over the investment of the Trust except to follow the directions issued.

(b) Except as provided in paragraph (a), in the administration of the Trust, the Trustee shall have the following powers:

(1) To hold and control the assets in the Trust;

(2) To sell, exchange, assign, transfer, and convey any security or property held in the Trust, at public or private sale, at such time and price and upon such terms and conditions (including credit) as directed by the Investment Manager;

(3) To invest and reinvest assets of the Trust (including accumulated income) as directed by the Investment Manager;

(4) To notify the Company of any vote on any stock or securities held in the Trust, as all voting rights with respect to Trust assets will be exercised by Company;

(5) To consent to and participate in any plan for the liquidation, reorganization, consolidation, or merger of any corporation, any security of which is held in the Trust;

(6) To sell or exercise any “rights” issued on any securities held in the Trust;

(7) To cause all or any part of the assets of the Trust to be held in the name of the Trustee (which in such instance need not disclose its fiduciary capacity) or, as permitted by laws, in the name of any nominee, and to acquire for the Trust any investment in bearer form, but the books and records of the Trust shall at all times show that all such investments are part of the Trust and the Trustee shall hold evidence of title to all such investments;

(8) To make such distributions to Participants (as such term is defined in the Plan) in accordance with the provisions of this Trust Agreement; and

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(9) From time to time the Company may appoint one or more investment managers who shall have investment management and control over all or a portion of the assets of the Trust (“Investment Managers”). The Company shall notify the Trustee of the appointment of the Investment Manager. In the event more than one Investment Manager is appointed, the Company shall determine which assets shall be subject to management and control by each Investment Manager and shall also determine the proportion in which funds withdrawn or disbursed shall be charged against the assets subject to each Investment Manager’s management and control. As shall be provided in any contract between an Investment Manager and the Company, such Investment Manager shall hold a revocable proxy with respect to all securities which are held under the management of such Investment Manager pursuant to such contract and such Investment Manager shall report the voting of all securities subject to such proxy on an annual basis to the Company. In the event that the Company does not appoint an Investment Manager as provided in this Section 5(i), references in this Trust Agreement to “Investment Manager” shall mean the Company.

Section 6. Disposition of Income.

During the term of this Trust, all income received by the Trust, net of expenses and taxes, shall be accumulated and reinvested.

Section 7. Accounting by Trustee.

Trustee shall keep accurate and detailed records of all investments, receipts, disbursements, and all other transactions required to be made, including such specific records as shall be agreed upon in writing between Company and Trustee. Within 60 days following the close of each calendar year and within 90 days after the removal or resignation of Trustee, Trustee shall deliver to Company a written account of its administration of the Trust during such year or during the period from the close of the last preceding year to the date of such removal or resignation, setting forth all investments, receipts, disbursements and other transactions effected by it, including a description of all securities and investments purchased and sold with the cost or net proceeds of such purchases or sales (accrued interest paid or receivable being show separately), and showing all cash, securities and other property held in the Trust at the end of such year or as of the date of such removal or resignation, as the case may be.

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Section 8. Responsibility of Trustee.

(a) Trustee shall act with the care, skill, prudence and diligence under the circumstances then prevailing that a prudent person acting in like capacity and familiar with such matters would use in the conduct of an enterprise of a like character and with like aims; provided, however, that Trustee shall incur no liability to any person for any action taken pursuant to a direction, request or approval given by Company which is contemplated by, and in conformity with the terms of the Plan or this Trust and is given in writing by Company. In the event of a dispute between Company and a third party, Trustee may apply to a court of competent jurisdiction to resolve the dispute.

(b) If Trustee undertakes or defends any litigation arising in connection with this Trust, Company agrees to indemnify Trustee against Trustee’s costs, expenses and liabilities (including, without limitation, reasonable attorneys’ fees and expenses) relating thereto and to be primarily liable for such payments, unless the litigation is a result of the Trustee’s negligence, bad faith or willful misconduct. If Company does not pay such costs, expenses and liabilities in a reasonably timely manner, Trustee may obtain payment from the Trust.

(c) Trustee may consult with legal counsel (who may also be counsel for Company generally) with respect to any of its duties or obligations hereunder.

(d) Trustee may hire agents, accountants, actuaries, investment advisors, financial consultants or other professionals to assist it in performing any of its duties or obligations hereunder.

(e) Trustee shall have, without exclusion, all powers conferred on Trustees by applicable law, unless expressly provided otherwise herein; provided, however, that if an insurance policy is held as an asset of the Trust, Trustee shall have no power to name a beneficiary of the policy other than the Trust, to assign the policy (as distinct from conversion of the policy to a different form) other than to a successor Trustee, or to loan to any person the proceeds of any borrowing against such policy. The Trustee shall not be liable for the failure or omission of any insurance company for any reason to pay any benefits or furnish any services under the policies or contracts.

(f) However, notwithstanding the provisions of Section 8(e) above, Trustee may loan to Company the proceeds of any borrowing against an insurance policy held as an asset of the Trust.

(g) Notwithstanding any powers granted to Trustee pursuant to this Trust Agreement or to applicable law, Trustee shall not have any power that could give this Trust the objective of carrying on a business and dividing the gains therefrom, within the meaning of section ###-###-####-2 of the Procedure and Administrative Regulations promulgated pursuant to the Internal Revenue Code.

(h) The Company shall indemnify and hold the Trustee harmless for any claims arising from its administration of the Trust, provided the Trustee acted in good faith in

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the discharge of its duties under the Trust. The Trustee shall not be liable for any action taken or omitted, or for any loss or depreciation of value of the Trust where the Trustee has exercised good faith and diligence in the exercise of its duties.

Section 9. Compensation and Expenses of Trustee.

Company shall pay all administrative and Trustee’s fees and expenses.

Section 10. Resignation and Removal of Trustee.

(a) Trustee may resign at any time by written notice to Company, which shall be effective 30 days after receipt of such notice unless Company and Trustee agree otherwise.

(b) Trustee may be removed by Company on 30 days notice or upon shorter notice accepted by Trustee.

(c) Upon resignation or removal of Trustee and appointment of a successor Trustee, all assets shall subsequently be transferred to the successor Trustee. The transfer shall be completed within 90 days after receipt of notice of resignation, removal or transfer, unless Company extends the time limit.

(d) If Trustee resigns or is removed, a successor shall be appointed, in accordance with Section 11 hereof, by the effective date of resignation or removal under paragraph(s) (a) or (b) of this section. If no such appointment has been made, Trustee may apply to a court of competent jurisdiction for appointment of a successor or for instructions. All expenses of Trustee in connection with the proceeding shall be allowed as administrative expenses of the Trust.

Section 11. Appointment of Successor.

(a) If Trustee resigns or is removed in accordance with Section 10(a) or (b) hereof, Company may appoint any third party, such as a bank trust department or other party that may be granted corporate trustee powers under state law, as a successor to replace Trustee upon resignation or removal. The appointment shall be effective when accepted in writing by the new Trustee, who shall have all of the rights and powers of the former Trustee, including ownership rights in the Trust assets. The former Trustee shall execute any instrument necessary or reasonably requested by Company or the successor Trustee to evidence the transfer.

(b) The successor Trustee need not examine the records and acts of any prior Trustee and may retain or dispose of existing Trust assets, subject to Sections 7 and 8 hereof. The successor Trustee shall not be responsible for and Company shall indemnify and defend the successor Trustee from any claim or liability resulting from any action or inaction of any prior Trustee or from any other past event, or any condition existing at the time it becomes successor Trustee.

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Section 12. Amendment or Termination.

(a) This Trust Agreement may be amended by a written instrument executed by Trustee and Company. Notwithstanding the foregoing, no such amendment shall conflict with the terms of the Plan or shall make the Trust revocable.

(b) The Trust shall not terminate until the date on which Plan participants and their beneficiaries are no longer entitled to benefits pursuant to the terms of the Plan. Upon termination of the Trust any assets remaining in the Trust shall be returned to Company.

(c) Upon written approval of participants or beneficiaries entitled to payment of benefits pursuant to the terms of the Plan, Company may terminate this Trust prior to the time all benefit payments under the Plan have been made. All assets in the Trust at termination shall be returned to Company.

Section 13. Miscellaneous.

(a) Any provision of this Trust Agreement prohibited by law shall be ineffective to the extent of any such prohibition, without invalidating the remaining provisions hereof.

(b) Benefits payable to Plan participants and their beneficiaries under this Trust Agreement may not be anticipated, assigned (either at law or in equity), alienated, pledged, encumbered or subjected to attachment, garnishment, levy, execution or other legal or equitable process.

(c) This Trust Agreement shall be governed by and construed in accordance with the laws of the State of Minnesota.

(d) The Trustee shall be entitled to rely on the accuracy of any information furnished to it by the Company or any other party from whom the Trustee is entitled to any information.

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Section 14. Effective Date.

The effective date of this Trust Agreement shall be January 1, 2005.

IN WITNESS WHEREOF, the Company and the Trustee have caused this Agreement to be executed by individuals thereunto duly authorized as of the day and year first above written.

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