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Virus & threat protection / Windows Defender update failed

Anonymous
2021-04-12T16:14:56+00:00

My virus & threat protection would not update and stated "Protection definitions are out of date."

Check the Windows Update first and try to download and install all updates first. This did not work for me.

Here was my fix that worked for me:

Complete the Method 1 here:

FIX: MMC.EXE This app has been blocked for your protection. (Solved) - wintips.org - Windows Tips & How-tos

After the reboot setting the UAC back to 1, the Virus & threat protection updated properly and started working again.

Windows for home | Windows 10 | Security and privacy

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

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  1. Anonymous
    2021-04-19T11:58:24+00:00

    A large number of Windows users have expressed concern that their computers' versions of Windows Defender would not be updated.

    The majority of these issues stem from Windows Defender failing to update virus definitions, which typically occurs when the user's internet connection is powerful. Even the Windows Update function is sometimes harmed, as it fails to update the system.

    Firstly,

    Look in 'Security' to see what software is classified under Virus Protection under Security and Maintenance. If a programme other than Windows Defender is specified, Windows Defender will not be allowed or operate properly.

    Secondly,

    1. To get started, go to the Windows security portal.

    2. To download and install the description updates, follow the on-screen instructions.

    3. If you can't install manually or are still getting update errors, there could be other issues, so contact Microsoft tech support for help.

    Updates are typically delivered by Microsoft via Windows Update, Automatic Updates, or the Windows Server Update Service (WSUS).

    Because of issues with these services, Windows Defender won't update in some cases. Manually update the meanings in this case, as defined above.

    If you were able to manually install updates, the problem is due to a Windows Update issue.

    10+ people found this answer helpful.
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  2. Anonymous
    2021-04-12T17:58:39+00:00

    In case of failure of update in Microsoft Defender, you need to check Windows Update first and try download and install all updates and fix the issue with Windows Update.

    I did make sure all Windows Updates were downloaded and installed first. I would hit the "Update" button on the Virus & threat protection and it would just hang and never complete the update so had to look for the solution.

    7 people found this answer helpful.
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  3. Reza-Ameri 45,806 Reputation points Volunteer Moderator
    2021-04-13T16:29:03+00:00

    The article you shared explained about registry editing which is not recommended in most cases. 

    In general we need to ask user to perform basic troubleshooting steps and if it didn't worked, we ask them to modify registries.

    3 people found this answer helpful.
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  4. Reza-Ameri 45,806 Reputation points Volunteer Moderator
    2021-04-12T16:57:15+00:00

    In case of failure of update in Microsoft Defender, you need to check Windows Update first and try download and install all updates and fix the issue with Windows Update.

    2 people found this answer helpful.
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  5. Anonymous
    2021-04-13T16:53:45+00:00

    The article you shared explained about registry editing which is not recommended in most cases. 

    In general we need to ask user to perform basic troubleshooting steps and if it didn't worked, we ask them to modify registries. 

    You are correct. I edited the post so that the first recommendation is to make sure you're up to date with the Windows update. Thanks!

    1 person found this answer helpful.
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