My iMac (Mountain Lion 10.8.3) was not shutting down properly for around year. It would be stuck with the grey spinning gear and wouldn't move from here.
I tried the Safe Mode: http://support.apple.com/kb/HT1455 and now it shuts down properly.
This fixed my issue and hope it helps someone.
I tried the Safe Mode: http://support.apple.com/kb/HT1455 and now it shuts down properly.
This fixed my issue and hope it helps someone.