Why a Spare Admin User Account Is Helpful
A spare admin user account hasn’t had changes made to its preference files. It also doesn’t contain any data beyond what macOS adds when the account is created. After you have administrative access to your Mac, you can reset your forgotten password and then log out and log back in with your regular account. You may be locked out of your Mac because you forgot your user account password or the Mac is acting up. In these cases, force the Mac to create a new administrator account with a new user ID and password. This method of gaining access to a Mac has a couple of drawbacks. It won’t work if you encrypted the Mac’s drive using FileVault or if you set up a firmware password for which you forgot the password.
How to Create an Admin Account in Single User Mode
To create a spare admin account, first turn off your Mac. If you’re not able to shut it down normally, press and hold the Power button. Once the Mac shuts down, restart it in a special startup environment called Single User mode. This mode boots the Mac into a Terminal-like interface where you can run commands from a prompt. :/ root# To restart the Mac in this special mode, remove the file that tells the OS whether the one-time setup process has been performed. At the command prompt, enter rm /var/db/.applesetupdone and then press Enter or Return.
