Three-Finger Swipe Down No Longer Switches Spaces in macOS 27.0.1

The behavior you describe —three finger swipe up, hover over a different fullscreen window (like a YouTube tab in fullscreen, or a different desktop space), and then swipe down three fingers on that window to swap to it— does not occur for me on my Mac running 27.0.1, but it also does not occur for me on my other Mac running 26.7.1. Rather, the normal behavior is that a three finger swipe down returns you to the Space where you entered Mission Control. This is from my Tahoe Mac, the cursor is hovering over a full screen YouTube video, but the Space from which I entered Mission Control (Desktop 2) remains highlighted by the blue box, and that's the space to which a three finger swipe down returns me.

To have Apple consider your feedback, submit it here:

Feedback - macOS - Apple

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.

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. 

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

Feedback - macOS - Apple

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.

W--R wrote:

I was mistaken in my wording - I meant being able to three finger swipe up from a fullscreen app, hover over one of the windowed applications open on my desktop, and then when I swipe down on that application, it would swap to that, instead of staying on the fullscreen space.

I'm on my 16" M1 Pro MBP running macOS Tahoe 26.7.1. I made this Safari window full screen, entered Mission Control with a three-finger swipe up, hovered the cursor over Desktop 3 and started swiping down with three fingers. You can see the full screen Safari window from which I entered Mission Control expanding as I swipe down...continuing the swipe down exits Mission Control and puts me right back on this full screen window, not onto Desktop 3 where the cursor was positioned.

EDIT: reading more carefully, you stated application window not the Spaces thumbnails. Okay, that behavior I can replicate. On Tahoe in the screenshot above, you can see that Desktop 1 is shown in Mission Control and if there are open windows on that Desktop (there weren't in my screenshot for privacy reasons) then I can three-finger swipe down to switch to that window/app. On Golden Gate, one difference is that the Desktop shown when entering Mission Control from a full screen app is the 'last' (highest-numbered) Desktop, not Desktop 1. A three-finger swipe down over a window on that Desktop does not switch to that app, but rather goes back to the full screen Space.

This is something only Apple can change. Tell them:

Feedback - macOS - Apple

I was mistaken in my wording - I meant being able to three finger swipe up from a fullscreen app, hover over one of the windowed applications open on my desktop, and then when I swipe down on that application, it would swap to that, instead of staying on the fullscreen space.

I don't recall it ever working that way. swipe up, select the space you want and click. that's how it's worked for me for as long as I can remember.

I see, I will make sure to let them know! Thanks for all the help!