Here is the scenario you go to log into a user account. You click user icon, type in the password, desktop starts to load, and boom it throws you back to the user login screen. You pop in your OSX disk, load up disk utility, repair permissions, reboot, and same thing. Of course you are either away from your time machine backup or you have not had a chance to backup a recent file that is important. You have a corrupted users profile that can not be repaired. Apples support article tells you to erase and reinstall OSX, but of course you need files first.

Here is what you do: (this also works if you forget your admin account password)

1. Boot into Single user mode by holding down Command-S (apple-S).
2. Issue the following commands
   

   • mount -uaw
   • cd /var/db
   • rm .applesetupdone

   Note: The hidden file you are deleting is what OSX uses to record if the initial setup was done. By deleting this file you are in essence telling OSX that the setup process was not done and to do it again.

3. Reboot by typing reboot
4. Listen to the warm and fuzzy music and register a new temporary user account.
5. You should now be able to log in and backup your files under the new account.