SOLVED High CPU Usage Due to Antimalware Service Executable

[siasbiwo]

Antimalware Service Executable is using 80% of my CPU. I've tried everything to stop it: disabling Windows Defender, adding the file to the exclusion list, and running a full malware scan, but nothing works. The only temporary fix is ending the process in Task Manager. This issue started a few days ago, possibly after an update. Setting the affinity to one core didn't help either. It seems like it needs to be fixed by an upcoming update.

 

[cheeseboxingLFG]

Go to Task Scheduler -> Task Scheduler Library -> Microsoft -> Windows -> Windows Defender. Disable or adjust the scheduled scan to run at a time when you're not using your computer.

 

[W10PowerUser]

Sometimes switching to a different antivirus solution can fix these issues. Just be sure to disable Windows Defender if you go this route to avoid conflicts.
Or you should limit CPU Usage for Windows Defender: Open Group Policy Editor (type gpedit.msc in the Run dialog), then navigate to Computer Configuration -> Administrative Templates -> Windows Components -> Microsoft Defender Antivirus -> Scan. Enable the Specify the maximum percentage of CPU utilization during a scan setting and set a lower percentage.

 

[Bball_CR7]

Hey, what worked for me was performing a clean boot to see if there were any startup programs conflicting with Windows Defender.

 

[siasbiwo]

Adjusting the scheduled scans did reduce the CPU usage a bit, but it's still higher than normal. I tried performing a clean boot, and the CPU usage went back to normal, so there seems to be a conflict with one of the startup programs. I'll start enabling them one by one to find the culprit. I'll also try the third-party malware scanners to make sure my system is clean and look into reinstalling Windows Defender if needed.
I'll keep you posted on my progress

 

[siasbiwo]

Great news, everyone! After following your suggestions, I managed to identify the culprit during the clean boot process. It turned out to be a third-party software that was conflicting with Windows Defender. I’ve disabled it, and my CPU usage has dropped back to normal levels! I also ran another tool as a precaution and my system is clean. Thanks so much for your help!