Microsoft has only just released Windows 11’s May security update, but it’s already causing issues. Version KB5013943 fixes a total of 75 vulnerabilities, but it fails to address an app crashing bug. In fact, installing it appears to make the problem worse.

The issue appears to affect apps that use the .NET Framework. As Windows Latest reports, users have complained about the following programs via Microsoft’s Feedback Hub:

  • Microsoft Teams
  • Discord
  • ShareX
  • KeePass
  • Visual Studio Installer
  • Corsair ICUE
  • Corsair Service

The bug doesn’t affect all users of these apps, but if you see this error message, you’ll know what’s causing it:

“The application was unable to start correctly (0xc0000135). Click OK to close the application.”

As a result, it’s worth holding off installing the update if you haven’t already. It’s technically mandatory, so may be automatically downloaded in the background, but installation requires a restart which you can avoid.

Microsoft is yet to release a fix, but two unofficial fixes may solve the issue for you.

How to fix Windows 11 KB5013943 app crashes

While we wait for an official patch, another potential solution is available. The bug appears to be caused by a compatibility issue between Windows 11 and the .NET Framework, so reinstalling both version 3.5 and 4.8 should solve the problem. Here’s how it’s done:

  1. Click the search icon next to the Start menu, then type ‘turn windows features on or off’
    Windows 11 fix app crashes
  2. Open the relevant option, and a window like below will appear
  3. Uncheck the boxes next to ‘.NET Framework 3.5 (includes .NET 2.0 and 3.0)’ and ‘.NET Framwork 4.8 Advanced Services’, then re-check them
  4. Click ‘OK’ to confirm, then restart your device to apply changes
    Windows 11 fix app crashes

If that doesn’t work and the app crashes are proving very disruptive, you can also uninstall the update completely. However, this process will only work if you installed it today or yesterday:

  1. Open Settings
  2. Click ‘Windows Update’ from the left pane, then ‘Update history’
    Windows 11 fix app crashes
  3. Scroll down to the section marked ‘Related settings’ and click ‘Uninstall updates’
    Windows 11 fix app crashes
  4. Any updates that have recently been installed are displayed here. Next to the KB5013943 update, click ‘Uninstall’, then ‘Uninstall’ once more to confirm
    Windows 11 fix app crashes
  5. Once complete, restart your device to apply changes

If that doesn’t solve the problem either, it may be caused by the earlier optional update where app crashes were first reported. In that scenario, or if more than a day has passed since you installed the update, you’ll need to wait for Microsoft to release a patch.

Related articles for further reading