For some time now I've had a problem with Norton Anti Virus for Mac (currently running OSX 10.6.3, but the problem existed even in earlier versions) not completing a scheduled scan. Seems when I set the scan for overnight at some point, usually around 70% complete (811144 of 1184105) it just hangs and I can't even cancel the scan. The only way to get rid of the scanning activity window is to reboot my Mac. I didn't report this before believing that the next upgrade would take care of it but it didn't. I suspect the problem may be related to Apple's screensaver, but even if it is this is not an Apple issue as far as I can tell. So is there a fix and how do I cancel the activity window when this happens?