How to fix KB5013943 causing application errors?

What causes How to fix KB5013943 causing application errors?

KB5013943 cumulative update installation
.NET Framework 3.5 not enabled
Windows Communication Foundation (WCF) components not activated
Windows Workflow (WWF) components not activated
Specific applications affected by the update

Offer Fortect PC Suite

Repairs Windows system files, removes malware, and restores a clean OS state — without reinstalling.

Ad · we may earn a commission

Hello. I recently installed the latest Windows updates and I keep receiving errors when I try to open my applications. What could be the problem?

Recently, Windows 11 users started experiencing errors when trying to launch certain applications. The issue seems to have started after people installed the latest KB5013943[ref en-1] cumulative update. The update was supposed to fix security vulnerabilities and bugs. Specifically, it had to fix a bug causing .NET Framework 3.5[ref en-2] apps not to open if they used the Windows Communication Foundation (WCF) and Windows Workflow (WWF) components.

However, now many people report specifically receiving the 0xc0000135 error when trying to use apps such as ProtonVPN, PowerShell, Event Viewer, Sound Blaster Command, KeePass, Visual Studio, Discord, and ShareX. The full error message reads as follows:

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

The KB5013943 update seems to have made the situation worse and users are flooding the forums looking for solutions. In this guide, you will find 3 steps that could help you fix the KB5013943 causing application errors. If they do not work, you may have to wait for Microsoft to release another fix.

You can also use a maintenance tool like [d1] that can fix most system errors, BSODs,[ref en-3] corrupted files, and registry issues. Otherwise, follow the step-by-step instructions below.

How to fix kb5013943 causing application errors

Method 1. Enable .NET 3.5 framework in the Control Panel

Go to Control Panel and click on Programs
Pick the Turn Windows features on or off option
Make sure .NET Framework 3.5 (includes .NET 2.0 and 3.0) and Net Framework 4.8 Advanced Services are checked

Method 2. Enable .NET 3.5 framework using Command Prompt

Type command prompt in the search and choose run as an administrator
Type in the following commands and press Enter after each one:

dism /online /enable-feature /featurename:netfx3 /all

dism /online /enable-feature /featurename:WCF-HTTP-Activation

dism /online /enable-feature /featurename:WCF-NonHTTP-Activation

Enable net 3 5 framework using command prompt

Method 3. Uninstall the KB5013943 Update

Before proceeding, keep in mind that this can leave your device unprotected from the latest security threats.

In Settings, from the left sidebar, select Windows Update
On the Windows Update page, click Update History

From the Related Settings section, choose Uninstall Updates
To remove an update, select it in the list and then click Uninstall

Click Yes in the prompt to continue

Bottom line

To fix the application errors caused by KB5013943, you can enable the .NET 3.5 framework through the Control Panel or Command Prompt, or uninstall the KB5013943 update. If these methods do not resolve the issue, you may need to wait for Microsoft to release another fix.

Frequently asked questions

What should I do if KB5013943 causes my applications to crash on Windows 10?

You can try uninstalling the update via Settings > Update & Security > Windows Update > View update history > Uninstall updates, then select KB5013943 to remove it.

Can I prevent KB5013943 from causing errors on Windows 11?

To prevent issues, you can pause updates temporarily in Settings > Windows Update, or check for any newer updates that may address the application errors.

How do I know if KB5013943 is the cause of my application errors on Windows?

Look for error messages or unusual behavior after installing the update, and consider checking forums or Microsoft's support page for reports from other users experiencing similar issues.

Did this fix work for you?

Written & verified by

Gabriel E. Hall

Malware Removal Expert

Malware removal Ransomware recovery Browser hijackers Spyware analysis Security tools testing

Gabriel E. Hall is a malware removal expert and cybersecurity researcher with over ten years of hands-on experience analysing threats and writing removal guides. She has documented hundreds of malware families — from browser hijackers and adware to ransomware and rootkits — providing step-by-step cleanup instructions tested against real infections. Gabriel's work combines deep technical analysis with clear, actionable language that readers without a security background can follow. Her guides consistently appear among the most-referenced resources for malware removal on Windows systems.

609 guides published LinkedIn ↗ All articles →

0 Comments

Be the first to comment