Windows Defender is inopperable aftrer uninstalling Norton 360.

Question

I am unable to open anything to do with "security."Windows 11. It keeps trying to find an app capable of opening a WindowsDefender file and directing me to locate the said file on the Microsoft Store, to no avail. All of this happened after removing Norton 360, packaged with my laptop. Once I began trying to uninstall it, I found "!" messages showing in the security section. Once there, I find that anything I try to click produces the same results...Sending me to find a WindowsDefender app that does not exist, as best as I know, at least.

Answer 1

1) Run the Norton uninstall tool to make sure that there are no remaining files:

https://support.norton.com/sp/en/us/home/current/solutions/v60392881
https://support.norton.com/sp/en/us/home/current/solutions/v15972972

2) Open administrative command prompt and type or copy and paste:

sfc /scannow
dism /online /cleanup-image /restorehealth
msdt.exe -id WindowsUpdateDiagnostic

3) Run the Windows firewall troubleshooter and Security troubleshooters:

https://support.microsoft.com/en-us/windows/automatically-diagnose-and-fix-problems-with-windows-firewall-513e9cf8-19ae-d579-2092-d5e64fe06f5f

https://support.microsoft.com/en-us/windows/automatically-fix-windows-security-issues-9041b976-e664-1a1d-0a82-607b0cbd7fc4

4) If the above command prompt commands and Microsoft Windows troubleshooters fail to fix problems with Windows 11 then perform an in place upgrade repair:

https://www.elevenforum.com/t/repair-install-windows-11-with-an-in-place-upgrade.418/

https://www.elevenforum.com/t/download-official-windows-11-iso-file-from-microsoft.1009/

https://www.microsoft.com/software-download/windows11

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Answer 2

Try open PowerShell as administrator and then type the following command:

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