- Restart your Mac or Hackintosh.
- Continuously press F8 until you see the Darwin boot prompt
- Type “-s” without the quotation marks and press enter.
- You will soon reach a command prompt
- Note the lines written to the console about fsck and mount
- Type : /sbin/fsck -fy
- Type : /sbin/mount – uw / this will mount your file system
- thats it now you are in “Single User Mode”
/sbin/fsck -y [enter]
/sbin/mount -uaw [enter]
passwd [usernamem] (put the administrators username, no the word username and take off the brackets)
type in a new password at prompt the two times it asks
type reboot
http://www.ihackintosh.com/2009/06/everything-about-single-user-mode-in-mac-os-x/