Now we need to reboot using the very logical reboot command.

Next we need to remove the file that tells OS X that its already done the setup: Most of the time this will just be your boot disk and can be mounted as '/'. The Mac will boot into Single User Mode you will need to mount the volume you need to get into. If you don't have an installer CD, you can achieve the same end as the CD method by a bit of commend-line footwork.īoot up the computer, holding 'Command' + 'S' as you hear the startup chime. Trick OS X Into Running the First Boot to Reset New Password

When you reboot the computer, you can use your new password to log into the computer. Enter a new password for that user and hit the save button. Instead, choose Terminal from the menu, type in 'resetpassword', and press 'Enter' to get to the password reset menu. If you're using the Mountain Lion installer, you won't see this menu item. You'll get a window prompting you to select the drive on which OS X is installed so choose the drive you want to get into and select the user whose password you want from the drop-down menu. Once it does, head up to Utilities in the menu bar and choose 'Password Reset'. If the computer in question doesn't have a CD drive, you can either hold 'Option' at boot and choose the 'Recovery partition' at startup, or put the Mountain Lion or Mavericks installer on a flash drive. It will boot into the Mac OS X installer. Just insert the CD into the target Mac and hold the 'c' key as you boot up the computer. If you have the Mac OS X installer CD handy, it's super easy to change the administrator account's password. Reset Mac Password with the OS X Installer

Mac master password reset