you say the serial number is for a different machine but it is the one I'm working on !!
you say the serial number is for a different machine but it is the one I'm working on !!
MacBook Pro 17″, macOS 10.13
On the Serial#, we're just other users here, you'll have to call Apple to get that straightened out.
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.
To find out if it's system wide or user specific, try this...
Open System Preferences>Users & Groups, unlock the lock, click on the little plus icon, make a new admin account, log out & into the new account.
Does it work in the new account?