Left Side Edge MacBook Screen is Cut Off

Hi there, Parris,

Thanks for visiting the Apple Support Communities. It sounds like your Messages app is not fully on the desktop of your Mac. We'd be happy to help.

First, if you have not already, try moving the Messages window over away from the edge of the display.

If that does not solve the issue, try the following:

1. Restart your Mac: Log out, sleep, wake, restart, or shut down your Mac - Apple Support
2. Check for, and install, any macOS updates (as this will also update the Messages app): How to update the software on your Mac - Apple Support
3. Restart into safe mode, and test the issue there: Start up your Mac in safe mode - Apple Support
4. See if it also occurs in a new user account: Set up users, guests, and groups on Mac - Apple Support

Best!

If that so backup your Mac using Time Machine Backup, Then restart your Mac with option, command and R pressed both.

Then click on Disk Utility, click on continue. Click on the Internal Drive and click on erase, make sure it is on macOS Extended(Journaled), then click on Erase, then, quit disk utility and then click on Reinstall macOS, click on continue, agree, select drive and install, then do the setup