Table of Contents
Windows Security Center displays "Unknown"
How to fix Windows Defender "Unknown" issue
Summarize
Home Computer Tutorials Computer Knowledge Fixed: Windows Security Shows Unknown in Windows 11/10 - MiniTool

Fixed: Windows Security Shows Unknown in Windows 11/10 - MiniTool

Apr 27, 2025 am 12:16 AM

Windows Defender displays "Unknown"? Virus and Threat Protection Shows "Unknown"? This article will provide several possible ways to resolve the Windows Defender "Unknown" issue in Windows 11/10.

Windows Security Center displays "Unknown"

Windows Security Center (Windows Defender) is an anti-virus software that comes with Windows systems that helps protect your computer from viruses, malware, and other threats. However, sometimes it may encounter some errors. For example, you may encounter issues such as "Invalid Windows Defender exclusions" and "Protect history not displayed."

This article describes another Windows Security Center error - Windows Security Center displays "Unknown". Let's first look at a real example:

I noticed this issue today, but wasn't sure when it started. My Windows Defender Security Center icon shows a yellow warning indicator on the taskbar and when I turn it on, all guards are marked "Unknown". I checked the protection update, the system downloaded an update, and after that all protections were marked "No action required". About an hour later, the warning indicator reappeared and this check update did not change the settings. They still show as "Unknown". I don't have any other antivirus software or security providers installed on my system.

What's the problem? How to solve it? Thank you so much.

If Windows Defender displays "Unknown", try the following fix:

How to fix Windows Defender "Unknown" issue

Method 1: Restart/refresh Windows Security Center Service

When the Windows Security Center service is disabled, Windows Defender displays "Unknown". In this case, enabling or refreshing the Windows Security Center service is the easiest way to fix the "Unknown" issue with Windows Defender. Please follow these steps:

Step 1. Enter Services in the Windows search box, and select Services from the best match results.

Step 2. In the Services window, scroll down to find and right-click Windows Security Center Services. If it is enabled, you need to select Refresh from the context menu. If it is not running, you should select Reboot.

If you are using an earlier version of Windows 10, you need to refresh or restart the Windows Defender service, such as the Windows Defender Security Center Service.

Fixed: Windows Security Shows Unknown in Windows 11/10 - MiniTool

Method 2: Repair or reinstall Windows Defender

If restarting the Windows Security Center service does not resolve the "Unknown" issue, you can try to fix Windows Defender.

Step 1. Enter "Windows PowerShell" in the Windows search box, then right-click it and select "Run as administrator".

Step 2. In the User Account Control window, select the "Yes" button.

Step 3. In the command line window, copy and paste the following command line, and press Enter:

Get-AppXPackage | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register “$($_.InstallLocation)\\AppXManifest.xml”}

Fixed: Windows Security Shows Unknown in Windows 11/10 - MiniTool

Wait for the process to complete, and then restart your computer. After that, check if the Windows Defender "Unknown" issue has been resolved. If not, you can uninstall and reinstall Windows Defender.

Method 3: Disable third-party antivirus software

Third-party antivirus software may conflict with Windows Defender, causing the Windows Security Center to display "Unknown". Therefore, to eliminate the "Unknown" error, you should disable or uninstall other antivirus programs from Control Panel or Windows Settings.

Method 4: Uninstall the most recent Windows updates

Many users have encountered Windows Defender "Unknown" issues after updating Windows. Therefore, uninstalling Windows updates is also an effective way to resolve "unknown" errors.

Additional Tips

If your files are lost after Windows update or downgrade, you can use the free data recovery software MiniTool Power Data Recovery to recover deleted files.

MiniTool Power Data Recovery can recover lost files (documents, pictures, videos, audio, emails, etc.) in a variety of data loss situations, such as recovering lost files after MBR is converted to GPT.

Click the button below to download MiniTool Power Data Recovery for free and try it out.

Summarize

Through this article, you should know what you can do when the Windows Security Center displays "Unknown". Try restarting the Windows Security Center service, repairing/reinstalling Windows Defender, turning off third-party antivirus software, and uninstalling Windows updates.

If you have any problems using MiniTool Power Data Recovery, feel free to send an email to [Email Address should be added here].

The above is the detailed content of Fixed: Windows Security Shows Unknown in Windows 11/10 - MiniTool. For more information, please follow other related articles on the PHP Chinese website!

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