Windows Update Error Code 66A

When booting the OS or shutting down the system, several Windows users are being prompted with the Windows Update Error Code 66a. Once confronted with this error, the users simultaneously face other issues such as slow processes, PC crashes, etc. Here are some potential fixes for this issue. So, have a read.

How to fix Windows Update Error Code 66a:

Run System in Safe Mode

You can go into Safe Mode by turning off your system then turning it on again. However, before the Windows begins to load, you must press the Shift + F8 keys together. This will open the Recovery Mode, and you can select to boot in Safe Mode.

For some, this method doesn’t work. They can use the System Configuration Tool to boot to Safe Mode.

Press together Windows + R keys to open Run

In the blank Run field, type msconfig and press OK

In the dialogue box, select Boot tab

In the Boot options, check the box beside Safe Boot and then click Apply and OK

Then click on Restart in the pop-up

The device will automatically boot to Safe Mode

To restart the Windows, normally uncheck the Safe Boot by following the same process above.

Once you are in Safe Mode, go to Start and type System Restore and press Enter

You now need to follow the prompts so the system can restore to a specific point. The process needs some time to complete. Once done, Restart the system as mentioned above

Safe Mode allows the system to run in basic files and drivers so you can restore the system to a point before getting the Error code 66a.

Run SFC Scan

Go to Start and type cmd in the Search bar

When you get the Command Prompt, select Run as Administrator

Type sfc /scannow (after the command)

The scan will begin and take some time

Once complete, you can restart the system – all the corrupted files will be replaced

Any corrupted files present in the system can cause this error. Fixing it also fixes the error.

Revert Windows Update Changes

Press the Windows + I keys together to open the Settings app

On this page, click on Update & Security

On the left pane, look for Recovery and click

You will get the option Go Back to Previous Version of Windows – click Get Started

Select Keep your Files and proceed with the reset process

When the recent updates are uninstalled, check to see if the problem is fixed

If the error has stopped, and then you wish to update Windows later, make sure the update is installed completely.

Rerun Windows Update

Open Start, and in the search box, type Windows Update and press Enter

The system will prompt the Windows Update option in the searched list

Click on Check for Updates to see if any updates are available – if Yes, then install them

Restart your system for updates to save

There are times when Windows update may be obstructed or halted in the background without your knowledge. An incomplete Windows Update can cause 66a error. Make sure the update is complete.

Execute a Clean Boot

Open Start and in the Search field, type msconfig and press OK

Select System Configuration

This will open a dialog box, and here, you must click on Services tab

Check the Hide all Microsoft services box and then click on Disable All

Then click on the Startup tab and click Open Task Manager

You need to right-click on all the processes and then select Disable

Close Task Manager and click OK

Restart your system

.NET framework dependant applications may sometimes cause conflict in software which in turn causes the 66a error. A clean boot frees the PC of any software conflicts and fixes the issue.

Check for Malware or Virus

The presence of malware in the system can compromise not just sensitive data but also the functioning of a system. A good anti-virus system ensures your system is free from such threats. Make sure you don’t ignore the warning messages prompted by the system when downloading third-party software that the system considers harmful.

Follow the above solutions to fix the Windows Update Error Code 66a.

Experiencing difficulties with your Device, check out our “How To” page on how to resolve some of these issues.


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