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Code 66a Error Windows Update [SOLVED]

Corrupted system files are likely to be at fault

6 min. read

Updated onApril 11, 2024

updated onApril 11, 2024

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Key notes

Are you wondering how to fix theWindows updateerror 66a? Do not worry! The Windows Report team has enlisted working solutions for you.

Windows users who experiencethecode 66a error reported PC crashes and slow PC processes, andtheError Code 66A .NET Framework prompt is displayed.

This error message appears during several instances, such as during Windows shutdown/startup, or while the .NET framework is running.

Meanwhile, we have compiled applicable solutions to fix theWindows updateerror code 66a. You can try out any of the enlisted solutions below to fix the problem.

How do I fix the error code 66a?

1. Run a SFC scan

TheSystem File Checkerscans for corrupt or missing system files and repairs them. You can perform the SFC scan by following the aforementioned steps.

2. Use a registry cleaner

Software leftovers, missing DLLs, and invalid Windows registry keys can also causeWindows updateerror code 66a problem.

Therefore, you can also use adedicated system restoration toolto check for file corruption or harmful software that resides on your PC. The tool will periodically scan your device and make sure everything is working.

3. Run the system restore in safe mode

Safe mode will start your PC in a diagnostic mode with only basic files and drivers running so you can perform a system restore to revert your system back to a point before you get the error message.

If you have never created a restore point before, give thishelpful guide about creating Windows 10 restore pointsa ready, then you may proceed to the next solution to undoWindows update.

4. Revert Windows update changes

5. Scan the PC for malware

Some Windows users ignore the warning message and they click on random links in the mail which contain hidden malware.

This ends up compromising their systems due to malware infection, their data and sensitiveinformation gets leaked to unauthorized access, or they get errors such as theWindows Update error code 66a.

The ideal step in order to prevent such things from happening is downloading and installing a third-party antivirus software that will deal with all virus-related problems.

This includes phishing, trojans, adware, spyware, and all the known and unknown threats that we usually have to deal with while browsing the internet.

Be safe, and choose a program that utilizes advanced AI and machine learning algorithms to monitor and quarantine suspicious activity.

⇒Get ESET HOME Security Essential

6. Uninstall the .net framework extended

7. Reinstall .NET Framework

Reinstalling .NET Framework can also fixWindows Updateerror code 66a problem. However, in order to reinstall .NET Framework, you have to fiddle with the Control Panel.

In addition, you may consider downloading several versions of .NET framework most especially the recent one. Check thisguide dedicated to fixing .NET Framework issuesfor more information.

8. Rerun Windows update

An incompleteWindows updatecan also result in theWindows Updateerror code 66aproblem.

Also, there are instances where the Windows Update process is halted or disrupted by the background process.

Therefore, we recommend that you rerun theWindows update; also, you should ensure the update process is completed. This should fix theWindows Updateerror code 66a problem.

9. Perform a clean boot

Software conflicts by.NET frameworkdependent applications can also cause theWindows Updateerror code 66a. These applications may run in the background whenever you start Windows.

Nevertheless, the clean boot starts up your PC devoid of any software conflicts. Therefore, you have to be logged on as the administrator before you proceed with these steps:

This concludes our article today. Here’s alist of the best tools to fix Windows update problemsin case you need more help with the subject.

Hope you are able to fixthecode 66a error in Windows Update problem by using any of the enlisted solutions above? Let us know if you have any questions. Feel free to comment below.

Code 66a Error Windows Update [SOLVED]#

How do I fix the error code 66a?#

1. Run a SFC scan#

2. Use a registry cleaner#

3. Run the system restore in safe mode#

4. Revert Windows update changes#

5. Scan the PC for malware#

6. Uninstall the .net framework extended#

7. Reinstall .NET Framework#

8. Rerun Windows update#

9. Perform a clean boot#