AMENDED AND RESTATED GUARANTY AGREEMENT

Exhibit 10.29

AMENDED AND RESTATED GUARANTY AGREEMENT

dated as of July 25, 2007

by and among

certain Subsidiaries of BLACKBAUD, INC.,

as Guarantors,

in favor of

WACHOVIA BANK, NATIONAL ASSOCIATION,

as Administrative Agent

TABLE OF CONTENTS

AMENDED AND RESTATED GUARANTY AGREEMENT, dated as of July 25, 2007, made by certain Subsidiaries (collectively, the “ Guarantors ”, each, a “ Guarantor ”) of BLACKBAUD, INC., a Delaware corporation (the “ Borrower ”), in favor of WACHOVIA BANK, NATIONAL ASSOCIATION, as Administrative Agent (in such capacity, the “ Administrative Agent ”) for the ratable benefit itself and the financial institutions (the “ Lenders ”) from time to time parties to the Amended and Restated Credit Agreement, dated of even date herewith (as amended, restated, supplemented or otherwise modified, the “ Credit Agreement ”), by and among the Borrower, the Lenders and the Administrative Agent.

STATEMENT OF PURPOSE

Pursuant to the terms of the Credit Agreement, the Lenders have agreed to make Extensions of Credit to the Borrower upon the terms and subject to the conditions set forth therein.

The Borrower and the Guarantors, though separate legal entities, comprise one integrated financial enterprise, and all Extensions of Credit to the Borrower will inure, directly or indirectly, to the benefit of each of the Guarantors.

It is a condition precedent to the obligation of the Lenders to make their respective Extensions of Credit to the Borrower under the Credit Agreement that the Guarantors shall have executed and delivered this Guaranty to the Administrative Agent, for the ratable benefit of itself and the Lenders.

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by the parties hereto, and to induce the Administrative Agent and the Lenders to enter into the Credit Agreement and to induce the Lenders to make their respective Extensions of Credit to the Borrower thereunder, each Guarantor hereby agrees with the Administrative Agent, for the ratable benefit of itself and the Lenders, as follows:

ARTICLE I

DEFINED TERMS

SECTION 1.1 Definitions . The following terms when used in this Guaranty shall have the meanings assigned to them below:

“ Additional Guarantor ” means each Subsidiary of the Borrower which hereafter becomes a Guarantor pursuant to Section 4.17 hereof and Section 8.11 of the Credit Agreement.

“ Applicable Insolvency Laws ” means all Applicable Laws governing bankruptcy, reorganization, arrangement, adjustment of debts, relief of debtors, dissolution, insolvency, fraudulent transfers or conveyances or other similar laws (including, without limitation, 11 U.S.C. Sections 544, 547, 548 and 550 and other “avoidance” provisions of Title 11 of the United States Code, as amended or supplemented).

“ Guaranteed Obligations ” has the meaning set forth in Section 2.1 .

“ Guaranty ” means this Amended and Restated Guaranty Agreement, as amended, restated, supplemented or otherwise modified.

SECTION 1.2 Other Definitional Provisions . Capitalized terms used and not otherwise defined in this Guaranty including the preambles and recitals hereof shall have the meanings ascribed to them in the Credit Agreement. In the event of a conflict between

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capitalized terms defined herein and in the Credit Agreement, the Credit Agreement shall control. The words “hereof,” “herein”, “hereto” and “hereunder” and words of similar import when used in this Guaranty shall refer to this Guaranty as a whole and not to any particular provision of this Guaranty, and Section references are to this Guaranty unless otherwise specified. The meanings given to terms defined herein shall be equally applicable to both the singular and plural forms of such terms.

ARTICLE II

GUARANTY

SECTION 2.1 Guaranty . Each Guarantor hereby, jointly and severally with the other Guarantors, unconditionally guarantees to the Administrative Agent for the ratable benefit of itself and the Lenders, and their respective permitted successors, endorsees, transferees and assigns, the prompt payment and performance of all Obligations of the Borrower, whether primary or secondary (whether by way of endorsement or otherwise), whether now existing or hereafter arising, whether or not from time to time reduced or extinguished (except by payment thereof) or hereafter increased or incurred, whether or not recovery may be or hereafter becomes barred by the statute of limitations, whether enforceable or unenforceable as against the Borrower, whether or not discharged, stayed or otherwise affected by any Applicable Insolvency Law or proceeding thereunder, whether created directly with the Administrative Agent or any Lender or acquired by the Administrative Agent or any Lender through assignment, endorsement or otherwise, whether matured or unmatured, whether joint or several, as and when the same become due and payable (whether at maturity or earlier, by reason of acceleration, mandatory repayment or otherwise), in accordance with the terms of any such instruments evidencing any such obligations, including all renewals, extensions or modifications thereof (all Obligations of the Borrower, including all of the foregoing being hereafter collectively referred to as the “ Guaranteed Obligations ”).

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SECTION 2.2 Bankruptcy Limitations on each Guarantor . Notwithstanding anything to the contrary contained in Section 2.1 , it is the intention of each Guarantor, the Administrative Agent and the Lenders that, in any proceeding involving the bankruptcy, reorganization, arrangement, adjustment of debts, relief of debtors, dissolution or insolvency or any similar proceeding with respect to any Guarantor or its assets, the amount of such Guarantor’s obligations with respect to the Guaranteed Obligations shall be equal to, but not in excess of, the maximum amount thereof not subject to avoidance or recovery by operation of Applicable Insolvency Laws after giving effect to Section 2.3 . To that end, but only in the event and to the extent that after giving effect to Section 2.3 such Guarantor’s obligations with respect to the Guaranteed Obligations or any payment made pursuant to such Guaranteed Obligations would, but for the operation of the first sentence of this Section 2.2 , be subject to avoidance or recovery in any such proceeding under Applicable Insolvency Laws after giving effect to Section 2.3 , the amount of each Guarantor’s obligations with respect to the Guaranteed Obligations shall be limited to the largest amount which, after giving effect thereto, would not, under Applicable Insolvency Laws, render such Guarantor’s obligations with respect to the Guaranteed Obligations unenforceable or avoidable or otherwise subject to recovery under Applicable Insolvency Laws. To the extent any payment actually made pursuant to the Guaranteed Obligations exceeds the limitation of the first sentence of this Section 2.2 and is otherwise subject to avoidance and recovery in any such proceeding under Applicable Insolvency Laws, the amount subject to avoidance shall in all events be limited to the amount by which such actual payment exceeds such limitation and the Guaranteed Obligations as limited by the first sentence of this Section 2.2 shall in all events remain in full force and effect and be fully enforceable against each Guarantor. The first sentence of this Section 2.2 is intended solely to preserve the rights of the Administrative Agent hereunder against each Guarantor in such proceeding to the maximum extent permitted by Applicable Insolvency Laws and neither such Guarantor, any Borrower, any other Guarantor nor any other Person shall have any right or claim under such sentence that would not otherwise be available under Applicable Insolvency Laws in such proceeding.

SECTION 2.3 Agreements for Contribution .

(a) To the extent any Guarantor is required, by reason of its obligations hereunder, to pay to the Administrative Agent or any Lender an amount greater than the amount of value (as determined in accordance with Applicable Insolvency Laws) actually made available to or for the benefit of such Guarantor on account of the Credit Agreement, this Guaranty or any other Loan Document, such Guarantor shall have an enforceable right of contribution against the Borrower and the remaining Guarantors, and the Borrower and the remaining Guarantors shall be jointly and severally liable for repayment of the full amount of such excess payment. Subject only to the subordination provided in Section 2.3(d) , such Guarantor further shall be subrogated to any and all rights of the Lenders against the Borrower and the remaining Guarantors to the extent of such excess payment.

(b) To the extent that any Guarantor would, but for the operation of this Section 2.3 and by reason of its obligations hereunder or its obligations to other Guarantors under this Section 2.3 , be rendered insolvent for any purpose under Applicable Insolvency Laws, each of the Guarantors hereby agrees to indemnify such Guarantor and commits to make a contribution to such Guarantor’s capital in an amount at least equal to the amount necessary to prevent such Guarantor from having been rendered insolvent by reason of the incurrence of any such obligations.

(c) To the extent that any Guarantor would, but for the operation of this Section 2.3 , be rendered insolvent under any Applicable Insolvency Law by reason of its incurring of obligations to any other Guarantor under the foregoing Sections 2.3(a) and (b) , such Guarantor shall, in turn, have rights of contribution and indemnity, to the full extent provided in the foregoing Sections 2.3(a) and (b) , against the Borrower and the remaining Guarantors, such that all obligations of all of the Guarantors hereunder and under this Section 2.3 shall be allocated in a manner such that no Guarantor shall be rendered insolvent for any purpose under Applicable Insolvency Law by reason of its incurrence of such obligations.

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(d) Notwithstanding any payment or payments by any of the Guarantors hereunder, or any set-off or application of funds of any of the Guarantors by the Administrative Agent or any Lender, or the receipt of any amounts by the Administrative Agent or any Lender with respect to any of the Guaranteed Obligations, none of the Guarantors shall be entitled to be subrogated to any of the rights of the Administrative Agent or any Lender against the Borrower or the other Guarantors or against any collateral security held by the Administrative Agent or any Lender for the payment of the Guaranteed Obligations nor shall any of the Guarantors seek any reimbursement from the Borrower or any of the other Guarantors in respect of payments made by such Guarantor in connection with the Guaranteed Obligations, until all amounts owing to the Administrative Agent and the Lenders on account of the Guaranteed Obligations are paid in full and the Commitments are terminated. If any amount shall be paid to any Guarantor on account of such subrogation rights at any time when all of the Guaranteed Obligations shall not have been paid in full, such amount shall be held by such Guarantor in trust for the Administrative Agent, segregated from other funds of such Guarantor, and shall, forthwith upon receipt by such Guarantor, be turned over to the Administrative Agent in the exact form received by such Guarantor (duly endorsed by such Guarantor to the Administrative Agent, if required) to be applied against the Guaranteed Obligations, whether matured or unmatured, in such order as set forth in the Credit Agreement.

SECTION 2.4 Nature of Guaranty .

(a) Each Guarantor agrees that this Guaranty is a continuing, unconditional guaranty of payment and performance and not of collection, and that its obligations under this Guaranty shall be primary, absolute and unconditional, irrespective of, and unaffected by:

(i) the genuineness, validity, regularity, enforceability or any future amendment of, or change in, the Credit Agreement or any other Loan Document or any other agreement, document or instrument to which the Borrower, any Guarantor or any of their respective Subsidiaries or Affiliates is or may become a party;

(ii) the absence of any action to enforce this Guaranty, the Credit Agreement or any other Loan Document or the waiver or consent by the Administrative Agent or any Lender with respect to any of the provisions of this Guaranty, the Credit Agreement or any other Loan Document;

(iii) the existence, value or condition of, or failure to perfect its Lien against, any security for or other guaranty of the Guaranteed Obligations or any action, or the absence of any action, by the Administrative Agent or any Lender in respect of such security or guaranty (including, without limitation, the release of any such security or guaranty);

(iv) any structural change in, restructuring of or similar change of the Borrower, any Guarantor or any of their respective Subsidiaries; or

(v) any other action or circumstances which might otherwise constitute a legal or equitable discharge or defense of a surety or guarantor;

it being agreed by each Guarantor that, subject to the first sentence of Section 2.2 , its obligations under this Guaranty shall not be discharged until the final indefeasible payment and performance, in full, of the Guaranteed Obligations and the termination of the Commitments; provided that a Guarantor may be released from the Guaranteed Obligations pursuant to Section 4.16 of this Guaranty.

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(b) Each Guarantor represents, warrants and agrees that its obligations under this Guaranty are not and shall not be subject to any counterclaims, offsets or defenses of any kind against the Administrative Agent, the Lenders or the Borrower whether now existing or which may arise in the future.

(c) Each Guarantor hereby agrees and acknowledges that the Guaranteed Obligations, and any of them, shall conclusively be deemed to have been created, contracted or incurred, or renewed, extended, amended or waived, in reliance upon this Guaranty, and all dealings between the Borrower and any Guarantor, on the one hand, and the Administrative Agent and the Lenders, on the other hand, likewise shall be conclusively presumed to have been had or consummated in reliance upon this Guaranty.

SECTION 2.5 Waivers . To the extent permitted by law, each Guarantor expressly waives all of the following rights and defenses (and agrees not to take advantage of or assert any such right or defense):

(a) any rights it may now or in the future have under any statute, or at law or in equity, or otherwise, to compel the Administrative Agent or any Lender to proceed in respect of the Obligations against the Borrower or any other Person or against any security for or other guaranty of the payment and performance of the Guaranteed Obligations before proceeding against, or as a condition to proceeding against, such Guarantor;

(b) any defense based upon the failure of the Administrative Agent or any Lender to commence an action in respect of the Guaranteed Obligations against the Borrower, any Guarantor or any other Person or any security for the payment and performance of the Guaranteed Obligations;

(c) any right to insist upon, plead or in any manner whatever claim or take the benefit or advantage of, any appraisal, valuation, stay, extension, marshalling of assets or redemption laws, or exemption, whether now or at any time hereafter in force, which may delay, prevent or otherwise affect the performance by such Guarantor of its obligations under, or the enforcement by the Administrative Agent or the Lenders of this Guaranty;

(d) any right of diligence, presentment, demand, protest and notice (except as specifically required herein) of whatever kind or nature with respect to any of the Guaranteed Obligations and waives, to the extent permitted by Applicable Laws, the benefit of all provisions of law which are or might be in conflict with the terms of this Guaranty; and

(e) any and all right to notice of the creation, renewal, extension or accrual of any of the Obligations and notice of or proof of reliance by the Administrative Agent or any Lender upon, or acceptance of, this Guaranty.

Each Guarantor agrees that any notice or directive given at any time to the Administrative Agent or any Lender which is inconsistent with any of the foregoing waivers shall be null and void and may be ignored by the Administrative Agent or such Lender, and, in addition, may not be pleaded or introduced as evidence in any litigation relating to this Guaranty for the reason that such pleading or introduction would be at variance with the written terms of this Guaranty, unless the Administrative Agent and the Required Lenders have specifically agreed otherwise in writing. The foregoing waivers are of the essence of the transaction contemplated by the Credit Agreement and the other Loan Documents and, but for this Guaranty and such waivers, the Administrative Agent and Lenders would decline to enter into the Credit Agreement and the other Loan Documents.

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SECTION 2.6 Modification of Loan Documents, etc . Neither the Administrative Agent nor any Lender shall incur any liability to any Guarantor as a result of any of the following, and none of the following shall impair or release this Guaranty or any of the obligations of any Guarantor under this Guaranty:

(a) any change or extension of the manner, place or terms of payment of, or renewal or alteration of all or any portion of, the Guaranteed Obligations;

(b) any action under or in respect of the Credit Agreement or the other Loan Documents in the exercise of any remedy, power or privilege contained therein or available to any of them at law, in equity or otherwise, or waiver or refrain from exercising any such remedies, powers or privileges;