KB5013943 / KB5012643 Windows 11 issues with .NET Framework 3.5 applications [Workaround]

[Update 11.05.22]: I’m bringing up the post again because the problem persists with KB5013943 on Windows 11. After installing the update, PowerShell (via the terminal) may fail to start and display an error message mscoree.dll is missing.

Other applications can also acknowledge the service with an error message, e.g. 0xc0000135, or not start at all. The workaround below is still valid.

{Original 05/04/22]: After Microsoft fixed the problem with KB5012643 under Windows 11 in safe mode via KIR, a new problem has now surfaced that can occur with some .NET Framework 3.5 applications. Microsoft is currently investigating this issue. But there is also a workaround for this.

As Microsoft writes, some .NET Framework 3.5 applications may experience problems or may not open at all. The affected applications use certain optional components in the .NET Framework 3.5, e.g. For example, the Windows Communication Foundation (WCF) and Windows Workflow (WWF) components.


  • KB5012643 or KB5013943 can be uninstalled if still possible. (Not recommended)
  • If this is not possible, then .NET Framework 3.5 and, if activated, the Windows Communication Foundation can be reactivated in the old Control Panel -> Programs and Features -> Activate or deactivate Windows features. (Recommended)
    • This can also be done quickly via the command prompt (administrator).
      dism /online /enable-feature /featurename:netfx3 /all
      dism /online /enable-feature /featurename:WCF-HTTP-Activation
      dism /online /enable-feature /featurename:WCF-NonHTTP-Activation (Optional)

Windows 11 tutorials and help

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