Shut Up Windows Security
OK I had an issue where a detected virus was literally removed, but it kept telling me it was there when security scanned. It was detected and REMOVED weeks ago. There used to be a clear history function, but there just is not anymore, and the detection was stuck in it's system and kept thinking it was there. The file was in a zip and the zip was never opened let alone running the app in it. The zip is gone from desktop, but it just would not shut up about it. Even if you allowed it, a few days later, there it is again telling you to take action.
Go to "C:\ProgramData\Microsoft\Windows Defender\Scans\History" Open all the directories and delete anything that can be deleted other then the 2 log files. Then open the log files (just like a text file) and delete everything in them, then save them. It will now get lost with telling you a virus is there when it's not. You can now scan again, and nothing will be found - no more nagging.