Windows update fails with error code 0x643

When installing updates using Windows update or Microsoft Update you may receive Error 0x643 or 0x80070643 (23 Oct-09)

http://support.microsoft.com/kb/976982

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Step #1 => Before doing anything else, write down what .NET Framework versions are currently installed:

How to determine which versions of the .NET Framework are installed and whether service packs have been applied

http://support.microsoft.com/kb/318785

Step #2 => Now see Resolution Method 2 in...

When you try to install an update for the .NET Framework 1.0, 1.1, 2.0, 3.0, or 3.5, you may receive Windows Update error code "0x643" or Windows Installer error code "1603" (ignore the title, if need be)

http://support.microsoft.com/kb/923100

After running the appropriate/needed tool, (re)install all .NET Framework versions manually using the download links on the page then run Windows Update manually to install security updates for same.

NB: If you remove .NET Framework 3.5 SP1 using the tool, reinstalling .NET Framework 3.5 will also install .Net Framework 2.0 SP2 and 3.0 SP2; then Windows Update will offer .NET Framework 3.5 SP1.

IMPORTANT! => If you remove .NET Framework 3.5 SP1, reinstall your .NET Framework versions in the following order:

    1. .Net Framework 3.5, then...

    2. .Net Framework 1.1, then...

    3. .Net Framework 1.1 SP1

NB: KB923100 references this page: http://blogs.msdn.com/astebner/archive/2006/05/30/611355.aspx.  Please read ALL of it as well as the related page http://blogs.msdn.com/astebner/pages/8904493.aspx before using the .NET Framework Cleanup Tool.

Step #3 => Check-in at Windows Update and install any critical security updates offered.

~Robear Dyer (PA Bear) ~ MS MVP (IE, Mail, Security, Windows & Update Services) since 2002 ~ Disclaimer: MS MVPs neither represent nor work for Microsoft

for several weeks I have been getting notified of an available update on a daily basis. I have tried to install it but it fails evry time with the following message >  Microsoft .NET Framework 1.1 Service Pack 1 Security Update for Windows 2000, Windows XP, Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2 (KB953297)

Could not be installed

Installing Microsoft .NET Framework 1.1 Service Pack 1 Security Update for Windows 2000, Windows XP, Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2 (KB953297) (update 1 of 1)...

Thanks for the information, but after following your direction I still got an error when installing .Net Framework 2.0 >> Error 25015.Failed to install assembly 'C\windows\microsoft.nt\framework\v2.050727\microsoft.visual basic.compatibility because of system error 0x80131107 – What does that mean? And how do I get around it?

Hi Swathi, thanks for your interest in solving my problem but it still tells me it can't install service pack 1. My error code when I try this installation is 643. This is a problem that has been ongoing for about a year now and I just let it go but now in trying to upgrade my Vista OS to Windows 7 it has come back to bite me, and tells me it needs it installed before preceding with the Windows 7 upgrade. Yesterday I did download the system readiness tool and then tried to download pack 1 from the Microsoft site and it failed. Today I did your suggestion of a clean boot with the same results. In the past all recomended downloads have installed correctly it's just service pack 1 that's been trouble.

Ocracoke19