Tricking your Mac into creating a new user account

1. Power on or restart your Mac (should work for any Mac OS X system).
2. At the chime (or grey screen if your chime is turned off), hold down Command+S on your keyboard to enter single-user mode.
3. This step is optional, but it’s a good idea because it checks the consistency of the hard disk before moving on. At the prompt, type fsck -fy and press Enter/Return. Wait for the checks to complete before going to the next step.
4. Type mount -uw / and press Enter.
5. Type rm /var/db/.AppleSetupDone and press Enter.
6. Type shutdown -h now and press Enter.