I've done a quick search and it doesn't seem that anybody else is having this issue from what I can see. After running today's update, trying out the App Store for the first time, I noticed that the icons for many of my apps have disappeared from the dock. They also don't show up in the Command-Tab floater window. I've tried logging out and rebooting but the problem persists. The problem is only with certain apps: Safari, iChat, Text Edit, Firefox, Address Book, Calculator, iPhoto... While other apps seem to be fine: Mail, Finder,iCal, iTunes, MS Office, System Preferences.... I can't seem to figure out a trend, I thought at first maybe it's only apps that are available in the App Store, but I don't think things like TextEdit and Dictionary are in there. Any ideas?? Oh ya, the icons do show up in the Apps folder and in the Get Info window for the apps in question.