It can be useful to create a backup admin user account in cases where you’ve been locked out of your Mac, for example because it’s frozen and you’ve already tried resetting the PRAM or SMC. In such cases, you may see a message saying, “Cannot log in to the user account at this time.”

A backup admin user account has no changes to its preference files, and it doesn’t contain any data beyond what macOS adds when the account is created. Once you have administrator access to your Mac, you can reset your forgotten password, then log out and log back in with your regular account.

You may have been locked out of your Mac because you forgot your user account password or because your Mac is acting strange. In these cases, force your Mac to create a new administrator account with a new user ID and password.

This method of accessing a Mac has a few drawbacks. It won’t work if you’ve encrypted your Mac’s drive with FileVault or if you’ve set a firmware password and forgotten the password.