Part of the endless stream of Windows updates that promise something and do something else entirely, the update called KB5012649 is one recognized even by Microsoft as a cause for application crashes.
According to independent investigations, the patch asks fortunately was proposed as an optional update induces many incompatibilities with common PC applications, the only possible solution immediately being to remove the source of the problems. The bad news is that the fix involves direct action from users, searching the Windows update list and finally uninstalling that patch is not that easy.
The update, released on April 25, came as a cumulative patch for Windows 11, incorporating numerous fixes for more or less important issues, dryly identified using the “Known Issues” description. But the interactions caused were anyway, just not simple. Once applied, the patch may cause some .Net Framework 3.5 applications to stop working.
Microsoft says: “Affected applications use certain optional components in the .NET Framework 3.5, such as the Windows Communication Foundation (WCF) and Windows Workflow (WWF) components. .Net Framework is ubiquitous in Windows and is used by various application developers as a code base that it can use. Some of these applications will now crash or not open with this update installed.
This update is only available to users who have already installed Windows 11 21H2 (latest).