Message on MAC

See if this helps..

Safe Boot, (holding Shift key down at startup), does the problem occur in Safe Mode? Could take 10 minutes.

Safe mode attempts to repair Disks & clears lots of caches & loads safe Drivers, & prevents loading of 3rd party extensions, so if Safe Mode works try again in regular boot.

You forgot your Mac's password. Here's how to get back into your locked-down computer

https://www.cnet.com/how-to/you-forgot-your-macs-password-heres-how-to-get-back-into-your-locked-down-computer/#:~:text=With%20your%20Mac%20turned%20off,up%20below%20the%20Apple%20logo.