Quick fix: Windows Defender update error 0x8050800c

Madalina Dinita
by Madalina Dinita
Former Managing Editor
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  • Updating Windows Defender is no complicated job. All you need to do is download the updates from Microsoft and then run them in Windows 10.
  • Every now and then, Windows Defender updates fail and the reasons behind this may vary.
  • If you're experiencing error 0x8050800c, make sure to follow these 4 steps listed below.
how to fix Windows Defender update error 0x8050800c
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Installing the latest Windows Defender updates helps you to keep your computer safe. Usually, Windows 10 will automatically download and install updates once a day for you. You can also download the latest updates manually.

However, there are instances when users can’t install the latest Windows Defender updates due to various error messages.

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Error 0x8050800c is one of the most frequent Windows Defender errors.

I am getting this error whenever I want to update the virus definition in Windows Defender. Sometimes the defender itself automatically turns off. […] The error code I am getting is: 0*8050800c. What should I do? I am using Windows 10.

If you’re experiencing error 0x8050800c, follow the instructions listed below.

How to fix Windows Defender update error 0x8050800c?

1. Restart your computer

  • First of all, you should try to restart your PC.
  • Then download and install the latest Windows Defender updates.

Users report that a simple action such as rebooting your computer eliminates error 0x8050800c and allows you to update your antivirus.

2. Install the latest Windows 10 Updates 

  • If there are any pending Windows 10 updates, install them first and then try to update Windows Defender. Many users confirm that this simple action solves the majority of Windows Defender Update errors.
  • Once you’ve installed the latest OS updates, restart your computer and try to update your antivirus.

3. Make sure you’re not running a third-party antivirus

It is possible that you’ve installed another antivirus program on your computer. If such is the case, this may explain why you can’t update Windows Defender. Uninstall the third-party antivirus solution and use a software removal tool as well.

If you’re a Norton user, we’ve got a dedicated guide on how to completely remove it from your PC. There’s a similar article for McAfee users, as well.

Did you know that your antivirus can block the internet connection? Check out this guide to find out more.

4. Clean your registry

If your system files are corrupted, Windows Defender may not be able to download and install the latest updates. In order to quickly scan and repair your registry, install a registry cleaner on your computer and let it do its job.

If you’re interested in repairing your corrupted system files, check out this useful guide that will help you do just that.

Looking for the best registry cleaners available right now? Take a look at this list with our top pics.

We hope the 4 solutions listed above helped you to fix Windows Defender‘s update issues. If you’ve come across other workarounds to fix error 0x8050800c, feel free to list the troubleshooting steps in the comment section below.

Also, leave there any other questions you may have and we’ll be sure to take a look.

Editor’s Note: This post was originally published in March, 2017 and has been since revamped and updated for freshness, accuracy, and comprehensiveness.

Editor's Note: This article was originally published in March 2017 and was revamped and updated in May 2020 for freshness, accuracy, and comprehensiveness.
  • None of the advice worked for me as is on Windows 7 64 pro UK as of 2019-04-08. I had:

    1. Restarted computer and manually downloaded Windows Defender definitions (mpas-fe.exe, File version: 1.291.1373.0, Digital signature timestamp: 2019-04-08). Did not work in normal mode.

    2. Installed all updates flawlessly (except the defender definitions of course)

    3. Never had external antivirus on this clean machine

    4. I installed CCleaner, but it actually made things even more unpleasant by silently installing Google Chrome on my system. Very, very uncool. How did this become such garbage?


    I started the computer in Safe Mode. I clicked on the mpas-fe.exe . I waited for a minute, rebooted to normal mode. THEN the Windows update offered me a smaller definition update and the final updates I was missing.

    So bottom line to resolve this for now is:

    1. Manually download definitions
    2. Restart in safe mode, install definitions (mpas-fe.exe)
    3. Restart in normal mode, check updates, update normally