After Installing Safari 4 beta yesterday, I noticed that Xcode started crashing on every run. Even when I uninstalled the Safari beta, the problem didn’t resolve. So I uninstalled Xcode completely and then reinstalled it. To uninstall developer tools/Xcode type in the following command in the terminal
sudo /Developer/Library/uninstall-devtools –mode=all
But beware, this completely removes Xcode and once it is gone, it’s gone. Of-course you can always reinstall it. So be sure of what you are doing.