macOS 27 – Mission Control/GUI performance and audio switching issues

M4 Mac mini running macOS 27 has Mission Control and audio switching issues

Since updating my M4 Mac mini to macOS 27, I’ve been experiencing two pretty significant regressions that weren’t present before the update.

Mission Control and general UI animations

Mission Control no longer behaves smoothly or consistently. The normal animations are sometimes extremely laggy, stutter, or appear to be missing altogether. At times, switching between desktops/windows feels like it’s running at a very low frame rate despite the Mac itself not being under any significant load.

This is an M4 Mac mini 16GB RAM, and the problem only appeared after updating to macOS 27. I’ve tried restarting, checking display settings and eliminating the obvious causes, but the behaviour persists.

It’s particularly noticeable because macOS normally has extremely smooth UI animations. Mission Control now feels considerably less responsive than it did before the update.

Audio output no longer switching automatically

I’ve also noticed that macOS is no longer reliably switching to an audio device when it becomes available.

For example, I can turn on my external speaker and the Mac recognises/connects to it, but audio continues playing through the previous output. I then have to manually open the audio controls/System Settings and select the speaker as the output device.

Previously, this happened automatically. Turning the speaker on was effectively all I needed to do.

Neither of these problems existed for me before macOS 27, and both affect very basic parts of the operating system that previously felt seamless.

I’m currently on macOS 27.0.1 on an M4 Mac mini.

Is anyone else on macOS 27/27.0.1 experiencing either of these issues, particularly:

• Mission Control animations stuttering, disappearing or behaving inconsistently

• General UI animation/frame-rate issues

• Audio devices connecting successfully but not automatically becoming the active output

• Having to manually select speakers/audio outputs that previously switched automatically

I’d be interested to know whether this is affecting other M-series Macs as well, and whether anyone running a macOS 27.1 beta has noticed any improvement.

There have been many issues reported with Mission Control and Spaces on macOS 27 Golden Gate, especially regarding the way Full Screen apps and app switching are handled. Some have been resolved by identifying and removing incompatible 3rd party extensions, others are bona fide bugs. The minor point update, macOS 27.0.1, did not appear to address the more significant issues.

Bugs should be reported to Apple here:

Feedback - macOS - Apple

See if the problem is present when you boot in safe mode. That process performs some system cleanup and clears caches, and also disables 3rd party extensions that may cause problems.

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.

In particular, the stuttering animations have been found by some users to be associated with TechTool Monitor, and other users have reported freezing/glitched and audio-related issues with 3rd party 'protection' software installed. If you have 3rd party ‘protection’ software installed, that may be the problem. That includes:

Cleaners (software claiming to automatically free up space)
Optimizers (software claiming to make your Mac run faster)
Antivirus software
VPN software (unless provided by a school/employer to enable access to internal resources from a remote location)

Such 3rd party system ‘helpers’, ‘cleaners’ and ‘protectors’ do more harm than good. In fact, such products are completely unnecessary for macOS and the only ‘good’ (if you want to call it that) they do is to put money in the developers’ pockets. Cleaners and protectors cause compatibility issues, often after macOS updates. Commercial VPNs claim to hide your browsing activity from websites, and while that may be true those VPN providers just sell your browsing data to others. For the user, all of these types of software offer only harm…and if that is limited to harm to your bank account, then count yourself lucky. If you have installed such software, follow the developer’s instructions to completely uninstall it (note that some developers fail to provide instructions and their software installs can be pervasive, meaning the only way to truly remove it is to erase your Mac, reinstall macOS then restore your user files from a backup).

If the issue persists in safe mode and a new user account, that suggests that it's a bug that Apple needs to address.

Reporting issues like this to Apple is the only way to get them fixed. They do prioritize bugs based on frequency of reports, so the more people who report it, the faster it will be addressed.

Personally, Mission Control is working fine for my use cases on my 16" M4 Pro MBP running 27.0.1. I have many Spaces and open windows, but I don't use full screen apps and I don't have my apps grouped, both of which are associated with reported issues. I have not experienced any audio issues, either with manually switching or automatic switching between internal speaker, AirPods, and a connected Thunderbolt (LG 5K:2K) display.

macOS 27 – Mission Control/GUI performance and audio switching issues

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