KB937986 failed, kept wanting to reinstall, + solution

MS Update kept telling me it needed to install KB937986 (Security update
for Virtual PC 2004 and Virtual PC 2004 SP1), and all attempts to install
kept failing.


The contents of KB937986.log in E:\Temp were:

Resource copy failed from E:\Temp\Virtual PC.exe to
C:\Program Files\Microsoft Virtual PC\Virtual PC.exe


The file E:\Temp\VirtualPC.exe was there (it wasn't even deleted after the
failed install), and the path on C: is the correct destination.
The version on E: was 5.3.0.583, that on C: was version 5.3.0.582, so the
copy operation was really failing.


I immediately suspected that it failed because my Temp directory is on
another drive, and the installer was attempting a fast move (within same
drive) instead of a copy. Not that I'm clearvoyant or all-knowing, but
ISTR having read about that problem with another update

Changing the "Temp" and "Tmp" environment variables to a directory on drive
C fixed the problem. After the update succeeded, I just reset them to E.