How do you unlock a frozen screen on a MacBook Pro?

Shut down. Then startup and go to recovery. Run disk utilities to repair drive. Shut down and try again, If still stuck , go back to recovery and reinstall.

Mac startup key combinations - Apple Support

If your Mac doesn’t start up as expected - Apple Support

Hold down the power button for about 10 seconds until it shuts down.

Hi,

In addition to the suggestions already posted, you may need to hold the power button down for about 10 seconds to shut down.

my screen is frozen on the system administrator log in page

how do i shut down on a macbook air