This is part of the underlying UNIX nature of MacOSX, and was the only place I found that gave clues to what was going on. I was able to get into single user mode (hold down Command-S right after the startup twang) and examine the /var/log/system.log file. I could log into the temporary admin account I give to Apple when the machine is sent in for service, so I knew it was something specific to my day-to-day account. Clearly something is hosed, and fortunately I was able to fix it.I tried the suggested solutions - booting in safe mode and logging in (still had the same problem) running a file system check in single user mode (no errors reported) deleting the login window plists and changing the password - but they had no effect.

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. 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.

After the release of the latest update to the Macintosh operating system (10.5.3), some users were reporting a 'login loop' to.These list items are microformat entries and are hidden from view.

Rebuild launch services clean my mac x