What to do if your Mac won’t shut down.
Occasionally you will tell your Mac to restart or turn off and a few minutes later you may discover that the Mac won’t shut down. Keep in mind that it could take three to five minutes to completely turn off since the Mac will shut down programs and save documents. You may need to save or discard changes in apps. If there is a bouncing icon on the dock it means that it needs attention.
You may need to Force Quit an app using the instructions in the section above, or if all else fails, hold the power button until the Mac turns off. Keep in mind that you can lose data if you do it this way.