Hi,
I will walk through a few steps with you. Some of these are just to help figure out what is wrong, not to fix it right away. So if nothing changes after a step, that is normal. I will keep going until we solve it.
- May I see the exact error or screenshot while using Defender?
In the Windows search,
Type Powershell, right-click it, and choose Run as Administrator.
Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage
Run this command and let me know if the issue persists after reboot.
I look forward to hearing from you to get the results of the troubleshooting.