I recall on older versions of Windows Defender (now Windows Security Center) that you could clear the threat history. I have found no such way in current versions of Windows Security Center. Is there a way to do this? I am on Windows 10 1903.
Delete folder Service C:\ProgramData\Microsoft\Windows Defender\Scans\History\Service .
After deleting the folder Service, off and turn on (OFF>ON) Real-Time protection and Cloud protection.