I have set both TEMP and TMP to C:\Temp, I ensured that C:\Temp exists and everyone has full privileges, and I checked the registry to ensure that both variables are correctly set. I point both to a single folder to make it easy to delete the unnecessary files on a regular basis (I abhor having to dig into both my profile and the system directory just to delete temp files). As stated in my original post, I have changed nothing in either Avast or the OS and this problem just started today.
