It's interesting that you thought it might be caused by the update.exe file. My computer BSOD'd as soon as the file was run, and even before any new files were written to their locations. Not only that, but the other day I had downloaded a custom SP4 update, to try it out, and it too crashed my system immediately after the files had been extracted to a temporary location. In both cases, I suspected the installer was part of the problem. It would be very nice if you could find the cause and then create updates that didn't conflict with Symantec. I'm always thankful for users, like harkaz, who have the skills to modify installers etc.