KB5015814: Critical security update corrupts Windows 11

KB5015814 is an important security update for Windows 11. But this patch of all things causes significant problems. You may need to uninstall it. All details.

Enlarge
KB5015814: Critical security update corrupts Windows 11.
The KB5015814 update released by Microsoft on patch day in July 2022 is causing trouble. This is reported, among other things, by the US IT news site Betanews.
KB5015814 is supposed to solve problems related to the Powershell framework and close security gaps; Microsoft explains the details in this blog post. However, after installing KB5015814, a few users report that the Windows Start menu no longer works properly. The app would keep opening and closing, killing the Start menu.
Affected users also report that Windows 11 would display various error codes: 0x8000ffff, 0x8007007e and 0x80073701. This occurs in such cases where the installation of KB5015814 would fail. Some users also report that Windows 11 would get stuck in an endless boot loop. While Microsoft has acknowledged some issues related to KB5015814, the error codes, failed installs, and Start menu issues mentioned are not among them.
Only workaround
Currently there is only one solution if KB5015814, which automatically installs Windows 11, causes you the mentioned problems: Uninstall the update. To do this, open the “Windows Update” area in the Windows 11 settings menu and look for the entry for KB5015814 in the update history. Then uninstall KB5015814 and then restart the computer.
However, since KB5015814 is also a security update, you should really only remove this update if it actually causes the problems described above.
Patch Day: Microsoft closes 0-day gap in Windows