Exhibit 10.20

THE
SECURITIES REPRESENTED BY THIS DOCUMENT HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR REGISTERED OR QUALIFIED UNDER APPLICABLE STATE SECURITIES
LAWS IN RELIANCE UPON EXEMPTIONS THEREFROM. THE HOLDER MAY NOT OFFER, SELL, TRANSFER, ASSIGN, PLEDGE, HYPOTHECATE OR OTHERWISE DISPOSE OF OR ENCUMBER THE SECURITIES REPRESENTED BY THIS DOCUMENT EXCEPT
PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT AND THE RULES AND REGULATIONS PROMULGATED THEREUNDER AND IN COMPLIANCE WITH APPLICABLE STATE SECURITIES LAWS, OR UPON RECEIPT
BY THE ISSUER OF AN OPINION OF LEGAL COUNSEL FOR THE HOLDER REASONABLY SATISFACTORY TO THE ISSUER AND ITS LEGAL COUNSEL THAT SUCH OFFER, SALE, TRANSFER, ASSIGNMENT, PLEDGE, HYPOTHECATION OR OTHER
DISPOSITION OR ENCUMBRANCE IS EXEMPT FROM THE REGISTRATION PROVISIONS OF THE SECURITIES ACT AND THE RULES AND REGULATIONS PROMULGATED THEREUNDER AND THE REGISTRATION AND/OR QUALIFICATION PROVISIONS OF
APPLICABLE STATE SECURITIES LAWS.

MSC.SOFTWARE CORPORATION

WARRANT TO PURCHASE COMMON STOCK  VOID AFTER 5:00 P.M., LOS ANGELES TIME, ON MAY 1, 2007

This certifies that, for value received, MICHAEL KORYBALSKI or registered assigns (the "Holder"), is entitled to
purchase from MSC.Software Corporation, a Delaware corporation (the "Company"), at any time on and after May 1, 2003, but no later than
5:00 P.M., Los Angeles time, on May 1, 2007 (the "Expiration Date"), at the purchase price of $15.00 per share (the
"Exercise Price"), up to 15,000 shares of Common Stock, par value $0.01 per share, of the Company (the "Warrant
Shares"). The number of Warrant Shares
purchasable upon exercise of this Warrant and the Exercise Price per share are subject to adjustment from time to time as set forth in this Warrant.



1.1Exercise.This Warrant may be exercised in whole or in part by presentation of this Warrant with the Purchase Form
attached hereto duly executed and simultaneous payment of the Exercise Price (subject to adjustment) at the principal executive offices of the Company, currently in the City of Santa Ana, California.
Payment of the Exercise Price shall be made at the option of the Holder hereof by certified or cashier's check or as provided in subsection 1.2 hereof. Upon any partial exercise of this Warrant, there
shall be countersigned and issued to the Holder hereof a new Warrant in respect of the Warrant Shares as to which this Warrant shall not have been exercised.

1.2Alternative Exercise.In lieu of exercising this Warrant for cash as described in subsection 1.1, the Holder shall have
the right to exercise this Warrant or any portion thereof (the "Net Issuance Right") into shares of Common Stock as provided in this subsection 1.2 at any time or from time to time during the period
specified in the first paragraph of this Warrant by the surrender of this Warrant (properly endorsed) to the Company. Upon exercise of the Net Issuance Right with respect to a particular number of
shares subject to this Warrant (the "Net Issuance Warrant Shares"), the Company shall deliver to the Holder (without payment by the Holder of any Exercise Price or any cash or other consideration)
that number of shares of Common Stock equal to the quotient obtained by dividing (X) the value of this Warrant (or the specified portion hereof) on the Net Issuance Exercise Date, which value
shall be determined by subtracting (A) the aggregate Exercise Price of the Net Issuance Warrant Shares immediately prior to the exercise of the Net Issuance Right from (B) the aggregate
fair market value of the Net Issuable Warrant Shares issuable

1

---

upon exercise of this Warrant (or the specified portion hereof) on the date the Net Issuance Right is exercised as provided herein by (Y) the fair market value of one share of Common Stock on
the date the Net Issuance Right is exercised as provided herein. For purposes of this subsection 1.2, fair market value shall mean the Closing Price (as defined in subsection 4.1(c)) of the Common
Stock on the date the Net Issuance Right is exercised as provided herein.

1.3Effect of Exercise.This Warrant shall be deemed to have been exercised immediately prior to the close of business on the
date of its surrender for exercise as provided in this Section 1 and the persons entitled to receive the shares of Common Stock issuable upon such exercise shall be treated for all purposes as
the holders of record of such shares as of the close of business on such date. As promptly as practicable on or after such date, the Company at its expense shall issue and deliver to the person or
persons entitled to receive the same a certificate or certificates for the number of shares of Common Stock issuable upon such exercise.



2.1Transfer.This Warrant shall be transferable only in the books of the Company upon delivery thereof duly endorsed by the
Holder or by his duly authorized attorney or legal representative. In all cases of transfer by an attorney, the original power of attorney, duly approved, or an official copy thereof, duly certified,
shall be deposited and remain with the Company. In case of transfer by executors, administrators, guardians or other legal representatives, duly authenticated evidence of their authority shall be
produced, and required to be deposited and remain with the Company. Upon any registration of transfer, the Company shall countersign and deliver a new Warrant to the person entitled thereto. Transfer
of this Warrant can be made only in compliance with all applicable federal and state securities laws.

2.2Exchange of Warrant.This Warrant may be exchanged for another Warrant entitling the Holder thereof to purchase a like
aggregate number of Warrant Shares as the Warrant surrendered then entitles such Holder to purchase. Any Holder desiring to exchange this Warrant shall make such request in writing delivered to the
Company, and shall surrender this Warrant. Thereupon, the Company shall countersign and deliver to the person entitled thereto a new Warrant as so requested.



There
have been reserved, and the Company shall at all times keep reserved out of its authorized Common Stock, a number of shares of Common Stock sufficient to provide for the exercise
of the right of purchase represented by this Warrant. The Company covenants that all shares of Common Stock issuable upon exercise of this Warrant will, upon issuance, be duly authorized, validly
issued, fully paid and nonassessable. The transfer agent for the Company's Common Stock and every subsequent transfer agent for any shares of the Company's capital stock issuable upon the exercise of
any of the rights of purchase aforesaid will be irrevocably authorized and directed at all times to reserve such number of authorized shares required for such purpose.



4.1Adjustments.The number and kind of securities purchasable upon the exercise of this Warrant and the Exercise Price shall
be subject to adjustment as follows:



2

---



3

---



4.2No Adjustment for Dividends.Except as provided in subsection 4.1, no adjustment in respect of any dividends made on a
quarterly or other periodic basis out of retained earnings shall be made during the term of this Warrant or upon the exercise of this Warrant.

4.3Preservation of Purchase Rights and Adjustment of Exercise Price upon Merger, Consolidation, etc.In case the Company
shall consolidate or merge with or into any other corporation (other than a consolidation or merger in which the Company is the surviving corporation and each share of Common Stock outstanding
immediately prior to such consolidation or merger is to remain outstanding immediately after such consolidation or merger and no cash, securities or other property is distributed with respect to such
shares) or shall sell or transfer all or substantially all of its assets to any person or entity, the Company or such successor or purchasing person or entity, as the case may be (collectively, the
"acquiring person"), shall execute an agreement that the Holder shall have the right thereafter upon payment of the Exercise Price in effect immediately
prior to such action to purchase upon exercise of this Warrant the kind and amount of shares and other securities, cash and other property that he, she or it would have owned or have been entitled to
receive after the happening of such consolidation, merger or sale had this Warrant been exercised immediately prior to such action (assuming that such Holder, as a holder of Common Stock prior to such
action, would not have exercised any rights of election as a holder of Common Stock as to the kind or amount of securities, cash or other property receivable upon such consolidation, merger or sale;
provided,

4

---

that if the kind or amount of securities, cash or other property receivable upon such consolidation, merger or sale is not the same for each non-electing share of Common Stock, then the
kind and amount of securities, cash or other property receivable shall be deemed to be the kind and amount so receivable by a plurality of the non-electing shares). The provisions of this
subsection 4.3 shall similarly apply to successive consolidations, mergers, sales or conveyances.



Nothing
contained in this Warrant shall be construed as conferring upon the Holder or his, her or its transferee the right to vote or to receive dividends or to consent or to receive
notice as shareholders in respect of any meeting of shareholders for the election of directors of the Company or any other matter, or any rights whatsoever as shareholders of the Company.



The
Company will not issue fractions of Warrant Shares. In lieu of such fractional Warrant Shares, there shall be paid to the Holder to whom fractional Warrant Shares would otherwise be
issuable an amount in cash equal to the product of such fraction of a Warrant Share multiplied by the Closing Price per share of Common Stock on the date this Warrant is exercised.



Any
notice pursuant to this Warrant by the Holder to the Company shall be in writing and shall be deemed to have been duly given if delivered or mailed by certified mail, return receipt
requested, to MSC.Software Corporation, 2 MacArthur Place, Santa Ana, California 92707, Attention: Louis A. Greco. Any notice mailed pursuant to this Warrant by the Company to the Holder shall be in
writing and shall be deemed to have been duly given if mailed by first-class mail, postage prepaid, to Holder at his, her or its address as it appears on the books of the Company. Each party hereto
may from time to time change the address to which notices to it are to be delivered or mailed hereunder by notice in writing to the other party.



This
Warrant shall be deemed to be a contract made under the internal laws of the State of California (without preference to conflicts of law principles) and for all purposes shall be
construed in accordance with the laws of said State.

IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by its duly authorized officers.

|Dated: |  | MSC.SOFTWARE CORPORATION
|------ |  | ------------------------
|       |  | By:                     
|       |  | ATTEST:                 

5

---

MSC.SOFTWARE CORPORATION  PURCHASE FORM

The undersigned hereby irrevocably elects to exercise the right of purchase represented by the within Warrant for, and to purchase thereunder,
            
shares of Common Stock, provided for therein, and requests that certificates for such shares of Common Stock be issued in the name of:

|Name:                                                |  | 
|---------------------------------------------------- |  | 
|Address:                                             |  | 
|Social Security or Taxpayer's Identification Number: |  | 

and, if said number of shares of Common Stock shall not be all the Common Stock purchasable thereunder, that a new Warrant for the balance remaining of the Common Stock
purchasable under the within Warrant be registered in the name of the undersigned Warrantholder or his or her Assignee as below indicated and delivered to the address stated below.

|Name of Warrantholder or Assignee:                   |  | 
|---------------------------------------------------- |  | 
|Address:                                             |  | 
|                                                     |  | 
|Social Security or Taxpayer's Identification Number: |  | 

|Signature:            |  |  |  | 
|--------------------- |  |  |  | 
|Dated:                |  |  |  | 
|Signature Guaranteed:

| |  | NOTICE: |  | The above signature must correspond with the name as written upon the face of this Warrant in every particular, without alteration or enlargement or any change whatever, unless this Warrant has been assigned.
| |  | ------- |  | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

6

---

ASSIGNMENT

(To be signed only upon
assignment of Warrant)

FOR
VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto

---

(Name
of Assignee)

---

---

---

(Address
and Social Security or other Taxpayer Identification Number of Assignee)

the
within Warrant, hereby irrevocably constituting and appointing

---

Attorney
to transfer said Warrant on the books of the Company, with full power of substitution in the premises.

DATED:

| |  | Signature of Registered Holder
| |  | ------------------------------

Signature Guaranteed:

| |  | NOTICE: |  | The signature of this assignment must correspond with the name as it appears upon the face of the within Warrant in every particular, without alteration or enlargement or any change whatever.
| |  | ------- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

7

---

QuickLinks