"You'll need a new app to open this windowsdefender link" fix

Hi this post is to help people with windows 10 and 11 windows security not working

On windows 11 do this

1. launch powershell as an admin
2. Set-ExecutionPolicy Unrestricted
3. Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
4. Set-ExecutionPolicy restricted

IGNORE THE ERRORS

on windows 10 do this

1. launch powershell as an admin}
2. run get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage
3. if it doesn't work do this
   4) run Add-AppxPackage -Register -DisableDevelopmentMode "C:\Windows\SystemApps\Microsoft.Windows.SecHealthUI_cw5n1h2txyewy\AppXManifest.xml"
4. run get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage

The Windows 11 fix worked for me, but ONLY when run by the user account that had the problem and first assigning that account to the Administrators group (and subsequently downgrading it back to Users). Other combinations ran (e.g. run by Administrator or by user before assigning as administrator) but failed to correct the problem.

This did work on my Windows 10. Just ignore the errors that you may get.

for windows 11 users:

try this command :

Add-AppxPackage -Register -DisableDevelopmentMode "C:\program files\windowsapps\Microsoft.SecHealthUI_1000.22621.1.0_x64__8wekyb3d8bbwe\appxmanifest.xml"

This also worked for me after everything else failed. It looks like McAfee managed to get itself installed on the machine, and when I uninstalled it, Windows Defender got broken.

Anyway, these three powershell commands fixed it - don't be freaked out by the number of error messages that you see in the console.

Fixed now ... downloaded Norton from BT