Today I installed Visual Studio 2008 SP1 and I accidentially detected that the installer created temporary files on a USB hard drive I just plugged in.
I can imagine what happens if I had unplugged it during the installation...
Why did the installer choose my external USB hard drive over the internal hard drive which is much faster?
Is there anything I can do to prevent something like this? Can it be configured using WSUS?
Windows Installer evaluates the drive with the highest amount of available space with the exception of network drives.
Then it generates a GUID as a folder name, which is why you end up with the names of 8ffa4cads222f11af33ae and the like. :)
I assume you mean an update that needs to be extracted from an archive before being run, and that is presented as a self-extracting archive that unzips itself to a temp folder called something like "dfgkjshdksnvlkdfnvshdf"?
I think it just uses the fixed drive with the highest available space. A USB HD will present itself to Windows - in certain scenarios - as a fixed drive (e.g. you can see it in Disk Management), so that's why it got used.
are you using vista and using the key for readyboost?