Windows 10: Why is Microsoft Defender Background task running if i did both offline and online scans...

Basically one time i was on my laptop and i went on this movie website and i wanted to watch Ted, Then a Ad popped up and i accidentally clicked it and it brought me to this website, i immediately exited the website and went to watch the movie until the sound wasn't working and i had to update it which i thought "hmm its probably a normal update like usual. And then it went to the Windows BIOS update screen which scared me since ive never saw it before and thought it was a virus, and so i waited as i was anxious then it went into the bitlocker recovery key screen. Later i went and put in the

:)

 

Defender Periodic Scanning or Offline Scanning?

That link does suggest it's useful to use Defender offline scanning in addition to periodic scanning and a third party real time anti virus (e.g. Kaspersky).

 

Microsoft Defender Offline Scan

Restored the Macrium Image and got my Recovery partitions back:






So as expected, I had a bunch of updates to do:





After the updates, I gave Microsoft Defender Offline a try and it worked!









And this just shows that I'm back at the latest version build of 20H2:





This one was my fault and I admit I was the culprit of my own troubles. It was just a coincidence that I used Partition Wizard around the same time the Cumulative Updates were going on from Oct 28th to November 11th and it gave me the suspicion to suspect them being responsible for the Offline scan problem.

I mean who the heck would of ever thought that a Recovery Partition would have anything to do with an Offline Scan in an Online world?

A special thanks to OldNavyGuy for his suggestion that a Windows Recovery Partition being deleted was the problem.

 

Windows Defender Running Background Scans Everyday

I'm trying to prevent Windows Defender from running a background scan everyday. The main reason is that it causes the fan on my laptop to run at full throttle for over an hour until the scan completes, but at the same time, a daily scan is overkill, especially with real time protection turned since it scans files on arrival.

I have tried changing numinous settings in order to disable the background scan, but Windows Defender insists that it needs to perform one everyday. Here's what I've tried...

• Disabled/Removed the Windows Defender scheduled scan entry in Task Scheduler. Still runs a background scan.
  
• Used Windows PowerShell (as admin) and Set-Mppreference to change the -ScheduledScanDay and -RemediationScheduleDay parameters from everyday to never. Still runs a background scan.
  
• Added a ScheduleDay REG_DWORD key in HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender\Scan with a decimal value of 8 for never. Still runs a background scan.
  

With all 3 of the above implemented, Windows Defender still runs a background scan, as indicated by the Antimalware Service Executable processes running at ~40% CPU usage. The background scan can be canceled while running and temporarily delayed if I open Windows Defender and turn off real time protection, wait several seconds, then re-enable it.

How do I stop the background scan from running everyday? I get the feeling that Windows Defender is just ignoring/overriding the registry policies and Mppreferences and is using its default settings.