MacOs 27 dock and spaces settings

There have been many issues reported with Spaces and Mission Control 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.

The failure to save app assignments to Spaces has been reported by at least one other user.

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 cleanupand 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. 

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 also don’t assign apps to specific Spaces.

I tried this in safe mode and with new user and it was the same. No third party apps on my machine.

what Claude suggested

THE PROBLEM

In the Dock, you can right-click an app and choose Options > Assign To to

make it open on a particular desktop. On macOS 27 these assignments go

back to "None" after the Mac sleeps.

WHAT WE FOUND

- The assignments are stored in the settings file com.apple.spaces,

under the key "app-bindings" (each app's ID is paired with a desktop ID).

- A before-and-after-sleep comparison showed that every desktop kept the

same ID. macOS simply deleted the assignments while the Mac slept.

- Only assignments to the LAST desktop survive (Script Editor, FileMaker).

- It makes no difference whether the app is open (Affinity was closed and

still lost its assignment).

- Conclusion: a macOS 27 bug. There is no setting that prevents it.

hopes this helps

Only Apple can fix bugs in macOS. Note that this is Apple Support Communities, not Apple Support. “We” are users like you and have no power to implement any suggestions. Apple employees are generally precluded from even reading these forums, with the exception of moderators who only monitor for compliance with the T&C.

Bugs should be reported to Apple here:

Feedback - macOS - Apple