Microsoft is encouraging its users roll back the latest optional Windows 11 update, as a result of issues it caused for some users.
Microsoft released update KB5012643 on April 25, but some users experienced issues with .NET framework 3.5 apps.
After installing KB5012643, some .NET Framework 3.5 apps might have issues or might fail to open. Affected apps are using certain optional components in .NET Framework 3.5, such as Windows Communication Foundation (WCF) and Windows Workflow (WWF) components.
The company is suggesting impacted users uninstall the update.
Workaround: To mitigate this issue, you can uninstall KB5012643. To do this, select the Start button and type, Windows Update Settings, and select it. On the Windows Update settings window, select View Update History then select Uninstall Update. Find KB5012643 in the list and select it, then select Uninstall.