UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 CheckFree Corporation - -------------------------------------------------------------------------------- (Name of Issuer) Common Stock, $.01 par value - -------------------------------------------------------------------------------- (Title of Class of Securities) 162813109 ------------------------------ (CUSIP Number) September 1, 2000 - -------------------------------------------------------------------------------- (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this schedule is filed: [_] Rule 13d-1(b) [X] Rule 13d-1(c) [_] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page. The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No.: 162813109 --------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSONS. 1 Microsoft Corporation S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON --------------------- - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2 (a) [_] (b) [_] - ------------------------------------------------------------------------------ SEC USE ONLY 3 - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4 State of Washington - ------------------------------------------------------------------------------ SOLE VOTING POWER 5 NUMBER OF 8,567,250 SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6 -0- OWNED BY ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7 REPORTING 8,567,250 PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8 -0- - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9 8,567,250 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10 [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11 11.3% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12 CO - ------------------------------------------------------------------------------ 2

Item 1 (a) Name of Issuer: CheckFree Corporation (the "Issuer") (b) Address of principal executive offices of Issuer: 4411 E. Jones Bridge Road, Norcross, Georgia 30092 Item 2 (a) Name of Persons Filing: Microsoft Corporation ("Microsoft") (b) Address of Principal Business Office: One Microsoft Way, Redmond, Washington 98052 (c) Citizenship: Microsoft is a corporation under the laws of the State of Washington (d) Title of Class of Securities: Common Stock, $.01 par value (e) CUSIP Number: 162813109 Item 3. Not applicable. Item 4. Ownership. (a) Amount beneficially owned: 8,567,250 (b) Percent of class: 11.3% (c) Number of shares as to which the person has: (i) Sole power to vote or to direct the vote 8,567,250 (ii) Shared power to vote or to direct the vote -0- (iii) Sole power to dispose or to direct the disposition of 8,567,250 (iv) Shared power to dispose or to direct the disposition of -0- Item 5. Ownership of Five Percent or Less of a Class: Not Applicable Item 6. Ownership of More than Five Percent on Behalf of Another Person: Not Applicable Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company: Not Applicable Item 8. Identification and Classification of Members of the Group: Not Applicable Item 9. Notice of Dissolution of a Group: Not Applicable 3

Item 10. Certification By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. September 11, 2000 ---------------------------------- Date MICROSOFT CORPORATION By: /s/ Robert A. Eshelman ------------------------------- Robert A. Eshelman, Assistant Secretary 4