Stop installing Win11 KB5012643: Microsoft confirms problem App Strike
If you want to update to Windows 11, then it's better to keep your hands to yourself, Microsoft has confirmed that there is a problem.
Now Microsoft has issued a warning that Windows 11 users may experience issues with certain types of applications after installing the KB5012643 update.
Microsoft has not made a specific announcement about this, but it has added a note in the Known Issues section of the Windows 11 release health page for version 21H2. The issue's title informs users that "some .NET Framework 3.5 applications may have issues" after installing KB5012643.
Microsoft explains this by saying, "Some .NET Framework 3.5 applications may have issues or may not open after installing KB5012643. Affected applications are using certain optional components in .NET Framework 3.5, such as the Windows Communication Foundation (WCF) and Windows Workflow (WWF) components." .
To alleviate this issue, users can choose to uninstall KB5012643. To do this, click the Start button and type "Windows Update Settings" and select it. In the Windows Update Settings window, select View Update History and then select Uninstall Updates. Find KB5012643 in the list and select it, then select Uninstall.