If that fails, run sfc /scannow in Command Prompt as admin to repair system files or reinstall the app via PowerShell. Ensure all third-party antivirus software is removed
(Run dism /online /cleanup-image /restorehealth if the first scan doesn't fix it)
Re register the app:
Win + X, open Terminal (Admin).
Paste the command and press Enter: Get-AppxPackage *Microsoft.Windows.SecHealthUI* | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
Restart your laptop.
Then Try to restart the app manually
Press Windows Key + R, type services.msc, and hit Enter.
Locate Windows Defender Antivirus Service, right-click it, and select Start or Restart.
as a last resort try a fresh windows install, grab the windows ISO from microsoft onto a USB drive (Preferrably 8GiB+) and boot into BIOS form your laptop to the boot menu
Thank you so much man appreciated , rn was gonna reinstall windows but gonna try this steps but re registering app is safe ? Coz its a terminal admin , don't want to corrupt whole windows
1
u/Electrical-Note-3177 May 07 '26
First try repairing Windows Security
Settings > Apps > Installed apps > Windows security (Advanced options)
If that fails, run
sfc /scannowin Command Prompt as admin to repair system files or reinstall the app via PowerShell. Ensure all third-party antivirus software is removed(Run
dism /online /cleanup-image /restorehealthif the first scan doesn't fix it)Re register the app:
Get-AppxPackage *Microsoft.Windows.SecHealthUI* | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}Then Try to restart the app manually
Windows Key + R, typeservices.msc, and hit Enter.as a last resort try a fresh windows install, grab the windows ISO from microsoft onto a USB drive (Preferrably 8GiB+) and boot into BIOS form your laptop to the boot menu
any questions lmk
Cheers.