This update is complete #@$#@$#@$. Totally hosed my system and given the sounds now emanating from my box could possibly be damaging my hardware. Reboots take up to fifteen minutes - random crashes with cocoa apps and a mysterious grinding noise from my system. As noted by many others there are SEVERE problems with this security update so be forewarned. I am reinstalling 10.2 and working my way up through the upgrades. This is the first major software problem I've had with OS X and is probably due to something I did but others might want to be very wary with this update.