Windows 10: Windows Defender full or custom scan maxes cpu

Hello!


I've been having issues with Windows Defender on Windows 10 for a while now. It started sometime during the summer, though I can't pinpoint the exact date. When I run a full or custom scan, Antimalware Service Executable will quickly start jumping up to 100% cpu and it makes my computer basically unusable for the duration of the scan. It's not a constant 100%, but while it does go up and down it spends a lot of time at or near 100%. It doesn't matter what drive I scan, this issue crops up a few minutes in. The automatic scheduled scans presumably work alright, since I've never actually noticed them happening.


It's not an issue with background processes, because when Defender is the only thing running it will just hog more %. The highest I've seen it go is 96% cpu for Defender alone. Windows Defender is my only antivirus, so it's not a conflict either.


I've tried googling for solutions and haven't really found anything helpful. I added an exception for MsMpEng.exe, but that did nothing. I can't set an affinity for this process, though some posts suggest that might be normal. I've updated Windows and everything is the most current version available.


I'd really appreciate any suggestions for resolving this. I need to be able to scan my whole PC, not just a quick or scheduled scan.

:)

 

Windows defender custom scan does not scan external drives

I have Defender Windows 10. I tried using custom scan to select and scan external drives. The screen listing the drives comes up, but the "OK" button remains grayed out so unable to scan any of the drives listed. Any suggestions would be appreciated.

 

Windows defender advanced scan extreme cpu overload


I routinely do Windows defender advanced scans. Up until about 2 weeks ago, that is.

All of a sudden the scan was completely maxing out my cpu. I wouldn't say it crashed the computer, but if I tried to do the simplest task while it was running, it rendered the machine unusable due to the draining of resources. Not to mention the scan would disappear, but was still running in the background. The only thing I could do at that point was to wait until it was done scanning, or shut down the unit

I found this thread that's about a year old, followed some of the suggestions, but nothing really helps.

I have no problem with the Quick scan.

High CPU usage when Windows Defender perform a Full Scan in Windows 10 - Microsoft Community

Windows Defender is my only virus protection, so there is nothing to create a conflict.

I put my defender installer folders in the excluded list. I changed my power settings from High Performance to Balanced.

I ran chkdsk /scan, sfc /scannow, dism /online /cleanup-image /restorehealth, and a Memory diagnostic. All normal.

Finally, I did a fresh install.

Is anybody else experiencing this?

 

Windows defender custom scan does not scan external drives

I tried the custom scan in Defender Windows 10. It brings up the list of drives but the "OK" button remains grayed out when I select any drive in the list, so still unable to scan external drives... Any suggestion would be appreciated.