I disabled windows defender realtime protection but its still scanning.

I recently upgraded from windows 10 to windows 11 with a clean install, and that's when I started noticing a problem.

I am doing development with python/pytorch, and some files I was working on were taking minutes to launch in windows 11, where they would start in seconds under windows 10. I narrowed the issue down to importing the pytorch library, and I noticed task manager shows quite a bit of activity from "Antimalware Service Executable - Microsoft Defender Antivirus Service".

So it seemed like I had found the problem, Defender was scanning the files in the library (it contains multiple gigabytes of dll files related to nvidia graphics) and that was slowing it down. So I did the sensible thing and added an exclusion for the folder. But, that didn't seem to stop it. Then I turned off the tamper protection setting, and the realtime protection setting. It still continued to scan when I import the library. I went as far as disabling realtime protection through the group policy editor, but still, nothing!

Just to confirm that I wasn't mistaken, I used Sysinternals Process Monitor to monitor MsMpEng.exe. As soon as I import the pytorch library, I can see it scanning these huge dll files that are contained within the folder that I excluded.

Is there anything else that I can try? I don't understand why it wont respect my decision to not keep scanning these files! I can't get anything done if I am waiting 1-2 minutes on it to scan every time!

Welcome to the forum. Your troubleshooting attemtpts are very thourough. But have you tried OPTION 2 regedit method in this tutorial.

My opinion is that this method should disable Defender in your current intallation, but when the system upgrades to a later vesion of windows that the regedit t would have to be done again.I just don't see your choice would carry over into a newer version of windows. I could be wrong about that, though.
Maybe @Brink can verify that.

Let me also note, unless you install a 3rd party AV solution, Windows may squawk with notifications that you are unprotected.

I did get a link here for a utility that fine-tunes Win 11 Defender, but I haven't tested it extensively yet.


Give it a try if you want

glasskuter said:

Welcome to the forum. Your troubleshooting attemtpts are very thourough. But have you tried OPTION 2 regedit method in this tutorial.

Enable or Disable Microsoft Defender Antivirus in Windows 11

This tutorial will show you how to enable or disable Microsoft Defender Antivirus in Windows 11. Microsoft Defender Antivirus is an antivirus software that is included in Windows 11 and can help protect your device from viruses, malware, and other threats. You must be signed in as an...

www.elevenforum.com

My opinion is that this method should disable Defender in your current intallation, but when the system upgrades to a later vesion of windows that the regedit t would have to be done again.I just don't see your choice would carry over into a newer version of windows. I could be wrong about that, though.
Maybe @Brink can verify that.

Click to expand...

I gave the regedit method a try and rebooted. Unfortunately, it continues to scan the files, and for some reason it was running MASSIVELY slower. I reverted the change, and it went back to the normal slow.

I'm thinking it is not Defender but may be Smart App Control that is the culprit. But if smart app control is disabled, it can not be enabled without doing a clean install or restoring an image made before it was disabled. I have mine turned off.

glasskuter said:

I'm thinking it is not Defender but may be Smart App Control that is the culprit. But if smart app control is disabled, it can not be enabled without doing a clean install or restoring an image made before it was disabled. I have mine turned off.

Click to expand...

Hmmm, mine is set to evaluation mode. I will research this some more to see if I want to turn it off. It seems kind of ridiculous that you can't just turn it back on once you turn it off.

glasskuter said:

I'm thinking it is not Defender but may be Smart App Control that is the culprit. But if smart app control is disabled, it can not be enabled without doing a clean install or restoring an image made before it was disabled. I have mine turned off.

Click to expand...

The smart app control was the culprit! After disabling it, its back to running at normal speed again. Thanks!

Brainstorming more here, so I'm just throwing out ideas for you to consider....some may be ridiculous.
Since those files are so large, could the issue be related to indexing? You might try excluding those large folders from being indexed..
You can check your search indexing status in realtime. Check Search Indexing Status in Windows 11

Great. Ignore my last post. I wrote it before I read that you had fixed