Microsoft: KB5012643 caused errors in some Windows 11 software

Microsoft rolled out an optional update KB5012643 to Windows 11 users at the end of the month, which itself is optional and is an update preview. At present, some users have found problems with the software after installing this update. There are many types of software involved, so it is unlikely that the software itself has problems.

Windows 11 Insider Preview Build 22572

We run an SQL-application (client and server on the same system) on Windows 11. That was running smoothly on Windows 7 and Windows 10. After installing Windows 11 update KB5012643, applications won’t start anymore. Apps do run again with no problems after uninstalling the update”, one of the affected users noted in the Feedback Hub.

Microsoft revealed in a support document that the update may cause software that requires the use of .NET Framework 3.5 to malfunction and recommends that users uninstall the update.

Microsoft said that after installing the optional update KB5012643, some software based on .NET Framework 3.5 may have problems such as failure to start. Affected software mainly uses optional components of .NET Framework 3.5 such as Windows Communication Foundation and so on.

Although Microsoft has marked this problem as mitigated, the actual mitigation method is to advise users to uninstall the update directly and not install optional updates for the time being. If the user is unwilling to uninstall or find it troublesome, they can also try to reinstall the .NET Framework 3.5. After reinstalling the framework, the software may be restored to use.

To uninstall the KB5012643 update, follow these steps:

  1. Click on the Start button and search Windows Update Settings.
  2. Windows Update settings window, select View Update History.
  3. Select Uninstall Update.
  4. Find KB5012643 in the list.
  5. Select the patch and click on Uninstall.

If the software still does not work after KB5012643 uninstallation, please try to reinstall the .NET Framework 3.5 through the following commands.

dism /online /enable-feature /featurename:netfx3 /all
dism /online /enable-feature /featurename:WCF-HTTP-Activation
dism /online /enable-feature /featurename:WCF-NonHTTP-Activation

Via: windowslatest