Unofficial archive. This is a read-only, community-run archive of the Apple Support Community. It is not affiliated with or endorsed by Apple Inc.
nastiakrava
User level: Level 1 (4 points)

After updating my Mac to the latest macOS version, I am experiencing severe UI glitches.

Hello.

After updating my Mac to the latest macOS version, I am experiencing severe UI glitches.


Windows fail to switch, the screen randomly turns black, the Dock does not hide properly and covers active apps, and the auto-hiding Menu Bar only triggers intermittently.


I have already restarted the Mac multiple times, all apps are updated, and there is plenty of free storage. It has been several days since the update, so background indexing should be complete.


Please help me resolve these system interface crashes or advise on recovery options.

Posted on Sep 23, 2026 3:40 AM

2 replies

neuroanatomist
User level: Level 9 (72,871 points)

Sep 23, 2026 4:40 AM in response to nastiakrava

Have you rebooted your Mac? If not, that's the first step. If that does not help, then see if the problem is present when you boot in safe mode. That process performs some system cleanup and clears caches, andalso disables 3rd party extensions that may cause problems.


in particular, issues like those you describe have been linked to techtool monitor.

 

Start up your Mac in safe mode - Apple Support

 

If that does not correct the issue, test in a new user account. A newly-created user account will have all settings at default, and if the issue does not occur in that new account then it provides guidance on what may need to be changed to correct the issue.

 

Add a user or group on Mac - Apple Support

 

Once the testing is complete, the new account can easily be deleted.

 

Delete a user or group on Mac – Apple Support

 

Those steps will help to isolate the problem.


It might help to download and run EtreCheck, written by a long-time forum member. The free version is fine. Post the full report using the Additional Text button. No personal information is revealed. 



WheelieNick
User level: Level 9 (74,110 points)

Sep 23, 2026 4:16 AM in response to nastiakrava

The severe UI anomalies you are experiencing—including black screens, windows failing to switch, and malfunctioning Dock/Menu Bar auto-hiding behavior—are known window-management and rendering bugs that frequently crop up immediately following major macOS updates. Since a simple restart and indexing did not fix it, the windowserver or preference configurations are likely corrupted. 

Originally posted at discussions.apple.com/thread/256363352