Fix High CPU Usage & Perfomance of Microsoft Security Essentials and Windows Defender

I use Microsoft Security Essentials on all my customer machines including my own.

I have noticed that on some, not all, of the machines that the CPU usage of Microsoft Security Essentials goes very high when doing anything.

After digging around it seems there is a bug in Microsoft Security Essentials where it keeps scanning itself as it is trying to work!

I have seen the problem on more XP machines, but have also seen it on 7 and 8.

The fix is easy. We simply tell Microsoft Security Essentials to exclude itself.

Go to your Microsoft Security Essentials, click on the "Settings" tab. Select "Excluded files and locations"

For Windows XP or any version of Windows running Microsoft Security Essentials:
Browse to "C:\Program Files\Microsoft Security Client\MsMpEng.exe"


For Windows 8 or anyone only using Windows Defender:
Browse to "C:\Program Files\Windows Defender\MsMpEng.exe"


Ok and press Add button to add the file to your list of excluded files and locations. Press Save changes button.

I have tested this on multiple machines and the CPU usage has finally started acting right, and scans have been even faster.

I have made this setting now part of my default settings when installing Microsoft Security Essentials.

Hope this is some help to you :-)

-Shane