Windows Defender not doing a full scan

Question

So I've been having this problem for a long while where Windows Defender full scan just doesn't scan fully, it scans like 80 files and stops. I think there is some type of virus or malware as whenever I start my laptop cmd pops up for a split second and runs something. I've googled and searched everywhere for a solution and tried lots of stuff such as sfc scan and everything is up-to-date. Any help would be appreciated.

Answer 1

Try update the Windows.
Run scan with Microsoft Defender Offline, have a look at:
https://support.microsoft.com/en-us/windows/help-protect-my-pc-with-microsoft-defender-offline-9306d528-64bf-4668-5b80-ff533f183d6c
Try boot into Safe Mode and run the scan and see if it works.