We think of 1Password as being helpful for entering passwords on websites and in iPhone and iPad apps. But its Universal Autofill feature has a hidden capability that lets 1Password enter your Mac login password when you have to provide it to change certain system settings, install apps, format drives in Disk Utility, and more. (But it won’t work to log in at startup before 1Password is running.) To turn this feature on, click the New Item button in 1Password, search for and select “Mac login” ➊, give it a name that will sort alphabetically to the top, like “2020 27-inch iMac” ➋, enter your password, and click Save ➌. From then on, whenever you’re prompted for your Mac login password, use 1Password Quick access by ➍, pressing Command-\ (Backslash, located above the Return key), and then using the arrow keys, select the proper login and press Shift-Return ➎.
