Hiding some users from macOS login screen

Installing software like Firebird DBMS adds users to your macOS system. In this particular case it added the user firebird, but I also wanted to toy around with the Firebird embedded variant, which has some magic for SYSDBA user. So I also added user named SYSDBA manually.

The problem is that my login screen now shows a bunch of accounts that cannot really be used. It's incredible that macOS has no GUI to simply exclude some accounts from the login screen. I guess it can pose a support problem down the line when people forget they hid some account and have no idea how to get it back... oh well.

Anyway, there's a way to at least bundle all of those accounts you don't need into a Other category. It's done with a command like this one:

sudo defaults write /Library/Preferences/com.apple.loginwindow HiddenUsersList -array-add username

The only problem is that this setting gets ignored after restart if you use full-disk encryption. Apparently the setting is stored in the encrypted part of the disk, and Mac shows the login screen before you decrypt it. Not really sure where it reads the list of users from in that case?

Tweet to @mbabuskov Milan Babuškov, 2021-10-29