Overview Error Code 643 (sometimes displayed as 0x80070643 ) is a common Windows Update failure on Windows 7. It typically appears when installing .NET Framework updates (e.g., KB2911501, KB2931356, KB2932079, KB2938772), Microsoft Office updates, or Windows system component updates.
net stop wuauserv net stop cryptSvc net stop bits net stop msiserver ren C:\Windows\SoftwareDistribution SoftwareDistribution.old ren C:\Windows\System32\catroot2 catroot2.old
net start wuauserv net start cryptSvc net start bits net start msiserver