Microsoft just fixed the
Safe mode issues in Windows 11, but the operating system
has apparently hit further problems with the latest cumulative
updates. KB5012643, which is an optional update with tons of
fixes, is crashing apps that use certain components of the .NET
If you’ve been using Microsoft’s desktop OS for a long time,
you’ve probably noticed .NET Framework. The .NET Framework
might appear in Windows Update or during the installation
process of certain apps. Many apps rely on .NET Framework to
function properly as it includes a collection of code that devs
can call when creating their apps.
Simply put, you just need .NET Framework for certain apps to
work. Unfortunately, a cumulative update apparently broke the
.NET Framework integration in the operating system and some
apps are now crashing. This is happening to those who have
installed the KB5012643 for Windows 11 version 21H2.
Previously, some users encountered Safe mode and installation
issues as well as Blue Screen of Death when installing this
particular optional update. As Feedback Hub posts highlight,
there are reports online documenting various issues in Windows
11’s latest update, including a bug where certain .NET 3.5
Framework apps crash.
“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.
Thankfully, this glitch does not affect all .NET 3.5
Framework-based apps. In a new update to a support
document originally published on April 25, Microsoft noted
that apps using certain components like Windows Communication
Foundation (WCF) and Windows Workflow (WWF) are affected.
We don’t have a list of affected apps, but if you’ve been
struggling to launch apps on Windows 11, now you know why.
Microsoft wants users to uninstall the update
So if you’re encountering app crashes on Windows 11, as the
user in Feedback Hub described and later confirmed by
Microsoft, it might be worth uninstalling the patch to see if
that makes any difference.
In the updated document, Microsoft’s first workaround
recommends removing the update manually. To uninstall the
update, follow these steps:
- Click on Start button and search
Windows Update Settings.
Windows Update settings window, select
View Update History.
- Select Uninstall Update.
- Find KB5012643 in the list.
- Select the patch and click on Uninstall.
Otherwise, the only other solution is to try your luck by
re-enabling .NET Framework 3.5 and the Windows Communication
Foundation on the Windows Features Settings page. You can also
run the following commands to perform this action via terminal:
dism /online /enable-feature /featurename:netfx3 /all dism /online /enable-feature /featurename:WCF-HTTP-Activation dism /online /enable-feature /featurename:WCF-NonHTTP-Activation
With these optional updates, there’s always a chance that you
will run into undocumented issues and that’s why
we don’t recommend optional cumulative or driver updates.
In addition to these issues, users are also reporting other
problems, including issues with Start, taskbar, USB and more.