Microsoft confirmed that third-party apps that allow users to customize the UI (the look of Windows) block the Start menu again.
The problem returned today with the latest Windows 11 update KB5028254 released for version 22H2. Microsoft says that ExplorerPatcher is currently down, but others (like Start11, etc.) may be affected.
“After installing KB5028254 or later updates, the Start menu may not open on Windows devices with certain third-party applications installed to change the appearance. The known affected third-party UI patcher is ExplorerPatcher, but others may also be affected. These types of applications often use unsupported methods to achieve customization and thus may have unwanted effects on the Windows device.
Solution: We recommend that you uninstall any third-party UI customization application before installing KB5028254 to prevent this problem. If your device is already experiencing this problem, you may need to contact the customer support of the app developer you are using.
Windows 11, version 22H2
As we mentioned above, this issue is not new and has affected Windows 11 22H2 in the past as well. Towards the end of February, earlier this year, when its update was released moment 2, the problem first appeared. This time though, it's the moment 3 affected.
Another issue that seems to be affecting Windows 11, as well as Windows 10 right now, is a video codec issue.
You can sit back and wait for the next updates, in the end maybe everything will work as it should.