Fixing a Mac OSX Leopard Login Loop Caused by Launch Services

After the release of the latest update to the Macintosh operating system (10.5.3), some users were reporting a “login loop” to MacFixIt.com. I followed the always helpful advice on MacFixIt for updating the operating system, and after the first reboot everything came back fine on my PowerBook G4 I thought I was in the clear. With the second reboot, though, I started seeing the login loop: the machine boots fine, but when you put the username and password in, the system hangs for about 20 seconds before displaying the login window again. Clearly something is hosed, and fortunately I was able to fix it.