Update failure for .NET / error 0x80070663

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

=====================

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 (but only the ones you wrote down in #1 above) 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/archi...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 Client - since 2002
www.banthecheck.com

baofulin wrote:
> My laptop running Windows XP SP3 is configured to automatically install
> updates. For quite some time now, Windows Update is trying to install an
> update to .NET each time i shut down. Each time it fails.
>
> Depending on something random (lunar phase? weekday?) that's either update
> KB974417 or KB951847. Update for KB951847 always fails with error code
> 0x80070663, KB974417 fails with error code 0x645.
>
> To me both updates look almost the same, so no idea why Windows Update
> should chose one or the other or actually chose to install both.
>
> No idea if this is related, but might well be the case: Some weeks ago
> automatic update failed, because the hard drive was full to the last
> kilobyte (hadn't done a clean up for a while). That time Windows couldn't
> shut down and obviously also couldn't start up again after the hard reset
> I
> had to execute. The system is fine now, except for this annoying behaviour
> with Windows Update. I suspect there's still a corrupt file stored
> somewhere that Windows Update refuses to download again.