Security Update error code



The automatic security download from Microsoft has tried several times to
download Microsoft .NET Framework 1.1 SP1 Security Update for Win2000 and
WinXP KB979906 and the installation has failed. Error code is O or 0x643.

I am using WinXP Home Edition, Ver 5.1 and SP3. No help from MX on-line
do-it-yourself stuff. Not sure what to do next. Any help or suggestions?

PA Bear [MS MVP]

[Crosspost to Windows Update newsgroup]

OPTION A: See the "How to obtain help" section of

For home users, no-charge support is available by calling 1-866-PCSAFETY
(1-866-727-2338; and/or 1-866-234-6020 and/or 1-800-936-5700) in the United
States and in Canada or by contacting your local Microsoft subsidiary.
There is no-charge for support calls that are associated with security
updates. When you call, clearly state that your problem is related to a
Security Update and cite the update's KB number (e.g., KB979906).

Or you can...

Start a free Windows Update support incident email request:

Customers who experience issues installing Microsoft security updates also
can visit the following page for assistance:

For more information about how to contact your local Microsoft subsidiary
for security update support issues, visit the International Support Web

For enterprise customers, support for security updates is available through
your usual support contacts.


OPTION B: First run the Fix It in this KB article & see if the update will
install after doing so:

How to fix MSI software update registration corruption issues

If no joy, see...

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

Then proceed per the following:


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

Step #2 => Now see Resolution Method 2 in this related KB article:

After running the .NET Framework Cleanup Tool (not the Windows Installer
Cleanup utility!), reinstall 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.

Download links for .NET Framework Cleanup Tool:



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: Please read
ALL of it as well as the related page before using the .NET
Framework Cleanup Tool.

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

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