Hi, I have an early 2008 iMac with 4Gbytes of RAM. I tried to update from OS X 10.8.3 to 10.8.4 via the App Store. Started the process and when I came back it seemed to have stalled saying it had 10 seconds to go... Came back in the morning and no change. Rebooted and couldn't login to any account.
What happens is that it lets me type the password and then the cog/circle starts spining in the password box and then nothing. Have left it going a long time >20 mins with no outcome. I tried the wrong password and it shakes the password box. So something is going wrong after the password is verified...
Rebooted using Command R and used the option of reinstalling OSX. While that completed successfully (eventually!) there was no change.
Getting desperate I then did a restore to the most recent time machine backup to 10.8.3 (this took 6 or 7 hours!). No success initially, but after trying the guest account which worked, I was able to login to the two accounts I tried (1x admin, 1x user). Then, while trying to restore my daughter's ipod (she forgot her passcode again!) I thought I'd browse the itunes store while it downloaded the latest ios... Things started to freeze as soon as I clicked on the store in itunes. I noticed that time machine had started a backup which probably didn't help. This iMac is really showing its age... Back to the some problem with login freezing/stalling.
I've tried renaming the keychain files (for all five accounts) as suggested by Yakito who seemed to have similar problems but this didn't work.
I'm now trying to restore to a 10.8.2 back up from March. Hope that works to get my daughter off my back.
Any ideas of what is going on here?
(PS I had no problems updating my mid 2011 Macbook Air to 10.8.4)