why is windows defender not working?

Question

So basicly i installed a virus then used the reset pc in settu=ings then now windows defender is now never working and is just showing a blank screen

Answer 1

Open Registry Editor.

Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SecurityHealthService.

In the right pane, make sure Start registry DWORD is set to 3.

P.S. If you're new to registry, create a System Restore point before above steps.

Answer 2

Hi. I'm David, and I'm happy to help you.

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Do the procedure below and see if you can open Windows Security:

1. Press "Windows + X" and select "Terminal (Admin)";
2. Type or paste the following command and press Enter:

Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage

3. Restart (not shutdown) your PC.

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If it persists, I suggest you do the procedure below:

1. Press "Windows + X" and select "Terminal (Admin)";
2. Type or paste the following command and press Enter:

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

Note: Several red warnings may appear when running this command. Ignore them. It's normal.

3. Restart (not shutdown) the PC.

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If the problem persists, please let me know.

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Feel free to ask back any questions.

Answer 3

If Windows Defender is not working and shows a blank screen after you reset your PC, there are several troubleshooting steps you can take:

1. Restart Your Computer: Sometimes, a simple restart can resolve issues with services not starting properly.
2. Check Windows Services: Ensure that the Windows Defender Antivirus Service is running:
   • Open services.msc from the Start menu.
   • Locate Windows Defender Antivirus Service and ensure its Startup Type is set to Automatic. If it is stopped, try starting it.
3. Remove Third-Party Security Software: If you have any third-party antivirus software installed, it may conflict with Windows Defender. Uninstall any such software and restart your computer.
4. Reset Microsoft Defender Antivirus: You can reset Microsoft Defender by running the following commands in an elevated Command Prompt:

      DISM /Online /Cleanup-Image /RestoreHealth
      sfc /scannow
   

5. Update Security Intelligence: Run the following command in an elevated Command Prompt to update the security intelligence:

      for /f "delims=" %d in ('dir "%ProgramData%\Microsoft\Windows Defender\Platform" /ad /b /o:-n') do if not defined _done "%ProgramData%\Microsoft\Windows Defender\Platform\%d\MpCmdRun.exe" -SignatureUpdate -MMPC
   

6. Check for Malware: Use the Microsoft Safety Scanner to check for any malware that may be affecting Windows Defender.
7. Contact Microsoft Support: If the issue persists after trying the above steps, consider reaching out to Microsoft Support for further assistance.

These steps should help you troubleshoot and resolve the issue with Windows Defender not working properly.

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References:

• Troubleshoot Microsoft Defender Antivirus service startup problems
• Troubleshoot Windows Defender or Endpoint Protection client