There are several things you can do to pinpoint the problem. What to do if you can't take a screenshot on Mac: 1. You can utilize the Preview tool to grab screens on Mac, next time you encounter the problem of ‘Screenshot on Mac not Working’ properly. If the mouse cursor is not moving at all, and the screen brightness / dimming and sound up / down buttons are not working on the keyboard, then the Mac is probably frozen and must be force rebooted.
Please try each step one at a time until you resolve your issue. You can do this in your System Preferences > Security & Privacy > Privacy > Screen Recording.
