SECURED PROMISSORY NOTE

Exhibit 10.2

SECURED PROMISSORY NOTE

(Mutual of Omaha Bank, Loan No. 3700038-001)

For value received, Quest Software, Inc., a Delaware corporation (“ Maker ”) promises to pay, in lawful money of the United States, to Mutual of Omaha Bank, a federally chartered thrift, or its order (“ Payee ”), at 4657 MacArthur Court, Suite 1480, Newport Beach, California 92660, Attention: James S. Knight, or at any other place as the Holder of this Secured Promissory Note (“ Note ”) may designate from time to time, the principal sum of Thirty-Four Million and No/100 Dollars ($34,000,000.00), which has been advanced by Payee to Maker under the concurrently executed Loan and Security Agreement (“ Loan Agreement ”), together with interest per annum commencing from the date of this Note at the applicable rate described below. As used in this Note, the term “ Holder ” will mean Payee, each Participant (as described in the Loan Agreement, to the extent of their interest), and each subsequent transferee or owner of this Note. This Note evidences a loan (the “ Loan ”) from Payee to Borrower, and is subject to the terms and conditions of the Loan Agreement. This Note, the Loan Agreement, and all other documents evidencing, securing, and guarantying the Loan are referred to collectively as, the “ Loan Documents ”.

1. Payment . Unless accelerated by Holder as a result of a default under this Note, all principal and accrued interest will be due and payable as follows:

(a) From the date of this Note (the “ Effective Date ”) until the Scheduled Maturity Date (as hereinafter defined), interest will accrue at the fixed rate equal to the Adjusted Treasury Rate, which is 7.03% (the “ Initial Rate ”). On the First Payment Date (as hereinafter defined) and continuing until the Scheduled Maturity Date, Maker will make equal monthly installment payments of principal and interest, in arrears, in an amount sufficient to fully amortize the principal balance of the Note and all accrued interest at the Initial Rate over an amortization period of 25 years.

(b) The first monthly payment will be due on the first day of the calendar month following the Effective Date (the “ First Payment Date ”) and then on the first day of each succeeding calendar month until the Scheduled Maturity Date. If the Effective Date is any day other than the first day of the calendar month, then interest on the principal sum outstanding for the period commencing on the Effective Date through (and including) the last day of the month in which the Effective Date occurs shall be due and payable concurrently with the payment that is due on the First Payment Date.

(c) The “ Scheduled Maturity Date ” is the date upon which all principal and interest is due and payable and is the date that is the 5th anniversary of the Effective Date.

(d) As used above, the term “ Adjusted Treasury Rate ” means a per annum interest rate equal to the greater of: (i) 6.25% per annum; or (ii) 5.0% over (in excess of) the Five Year Treasury Rate. The term “ Five Year Treasury Rate ” means the Five Year

Treasury Constant Maturity rate as determined by the United States Treasury and published by the Federal Reserve Board as of the date of Lender’s commitment letter.

(e) Interest will be calculated based upon a 360-day year and the actual number of days elapsed. This results in more interest than if a 365-day year were used. All amounts payable under this Note are payable in lawful money of the United States during normal business hours on a Banking Day (as such term is defined in the Loan Agreement).

2. Default . Maker will be deemed to be in default under this Note if Maker: (i) fails to make any payment required under this Note within ten (10) days after the date the payment is due, or if there is not specified due date then within 10 days after written notice from Lender; (ii) is in default (monetary or non-monetary) beyond all applicable notice and cure periods under the Deed of Trust (as defined below) or under any of the other Loan Documents. If Maker is in default under this Note, or under any other Loan Documents, the unpaid principal and accrued and unpaid interest and any other unpaid amounts and costs due will bear interest at a rate (“ Default Rate ”) equal to 5% greater than the applicable rate of interest then being charged under the Note. From and after the date when the principal balance of this Note is due by reason of its scheduled maturity, acceleration, default, or otherwise (the date being called the “ Maturity Date ”), any unpaid principal and interest and any other unpaid amounts and costs under this Note will bear interest at the Default Rate. Additionally and without limitation, all amounts owed under any judgment obtained against Maker with respect to this Note will bear interest at the Default Rate.

3. Late Charge . Without limiting Holder’s right to charge and collect interest at the Default Rate upon the occurrence of the specified events, Maker acknowledges that, if any payment required under this Note is not paid within 10 days after the date the payment is due, the Holder will incur additional costs. The exact amount of these costs is difficult and impracticable to assess. Maker acknowledges that, under the circumstances existing at the time this Note is made, the sum equal to the greater of $100.00 or five percent (5.00%) of the overdue amount is a reasonable charge, and Maker promises to pay this late charge when due. No notice of the assessment of the late charge need be given by Holder to Maker. The obligation of Maker to pay the late charge does not alter or affect the rights of the Holder to collect interest on the amounts due under this Note at the interest rates established in this Note nor does it affect or impair Holder’s other rights or remedies under this Note or any other Loan Documents.

4. Usury Limitation . Maker agrees to pay, and has contracted with Holder to pay, an effective rate of interest that, together with the interest rates described in this Note, results from the inclusion of