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I have a iMac 21.5inch from late 2015. When ever I play a video on full screen or my screen saver goes off, it completely freezes my Mac to the point I have to reboot it. The screen also slightly flickers sometimes. I have 750 gb left. This started happening when I upgraded to Big Sur. What could be the issue? Thank you.
iMac Line (2012 and Later)
Boot into Safe Mode by booting with the Shift key held down and check there to see if the problem persists. Reboot normally and test again.
NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following;
• Verifies your startup disk and attempts to repair directory issues, if needed
• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)
• Prevents Startup Items and Login Items from opening automatically
• Disables user-installed fonts
• Deletes font caches, kernel cache, and other system cache files
Boot into Safe Mode by booting with the Shift key held down and check there to see if the problem persists. Reboot normally and test again.
NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following;
• Verifies your startup disk and attempts to repair directory issues, if needed
• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)
• Prevents Startup Items and Login Items from opening automatically
• Disables user-installed fonts
• Deletes font caches, kernel cache, and other system cache files
Going Fullscreen Freezes my iMac
