I ran into an oddity today that took me an hour to resolve. Two Microsoft Update patches, Microsoft Word and Microsoft Expression, would NOT install. Both were receiving the exact same error message from the Microsoft Installer application, “Update for…insert update name here…failed to install”.
Even after killing most running applications, disabling virus scan and spyware apps, I was still running into issues. I tried clearing all temp locations, downloaded activex controls, etc. I am pretty thorough when it comes to troubleshooting my PCs. All to no avail.
I eventually resorted to downloading the updates manually, installing each, and enabling logging for both. After manually installing (and failing) I was able to locate the “critical” install error (return value 3) from the log files reporting that the installer was unable to manipulate the following registry key:
Apparently, an incomplete/failed installation of another program caused a problem with the same key removing all available r/w permissions resulting in a failed installation of both updates.
The resolution was to delete the .xml key completely. After deleting the .xml key, both updates ran without any problems. I would imagine you could also manually enable the appropriate permissions, if you are unsure of whether or not to completely delete the .xml key. It should not cause any problems either way (as long as you do NOT lock the key down!)