Why does my MacBook Pro have a flashing folder with a question mark
Why does mi Mac Pro Java a folder with a question mark when powered up?
MacBook Pro
That means Hard Drive problems, it may be dead or dying.
Start with this...
Safe Boot, (holding Shift key down at startup), does the problem occur in Safe Mode? Could take 10 minutes or more.
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.