Single-user mode doesn't last?

[Chuma]

I'm trying to start in single-user mode, by holding down cmd+s. I see a lot of tiny white text flashing by, occasionally pausing for a couple of seconds but not letting me do anything. Then the regular login window pops up. There is no firmware password set, so as far as I can tell, I should be able to access single-user mode. What could be causing this?

OS version is 10.14.6.

 

[Taz Mangus]

If your computer is a 2018 model then command-key s-key won't work.

Start up your Mac in single-user mode or verbose mode

If you're an advanced user who is comfortable with UNIX, you can use single-user mode or verbose mode to help isolate issues related to startup.

support.apple.com