Reset Windows Security:
- Open Settings.
- Click on App settings
- Search for Windows Security
- Click on the 3 dots and select Advanced option
- On the next page, click on the Reset button in Settings.
- Click on Reset to confirm.
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Reset via PowerShell (as Admin)
copy-paste the following command:
Get-AppxPackage Microsoft.Windows.SecHealthUI | Reset-AppxPackage
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You can also reinstall the app via PowerShell (admin)
PowerShell -ExecutionPolicy Unrestricted -Command "& {$manifest = (Get-AppxPackage Microsoft.Windows.SecHealthUI).InstallLocation + '\AppxManifest.xml' ; Add-AppxPackage -DisableDevelopmentMode -Register $manifest}"