MsMpEng.exe

[FC, Dublin]

Why does MsMpEng.exe use up all of my cpu when scanning & and can I do
anything about it?

 

[Bill Sanderson]

Scanning can be intense. The scanner has to create cryptographic hashs of
the files that it tests to compare to a list of bad files.

Are you doing a full scan, or a quick scan? I would encourage you to do a
quick scan, and reserve a full scan for when something is found, or on some
less frequent scheduled basis.

 

[Stephen Boots MVP-Windows Live]

Why does MsMpEng.exe use up all of my cpu when scanning & and can I do
anything about it?

When this happens to OneCare users (the same scanning engine in
Defender and OneCare) the problem is almost always caused by a
conflict with other software on the PC, typically security software
that provides real time protection/scanning. Basically, each file that
the engine touches to look at, the other protection software
intercepts to check, too, and a deadlock occurs.
-steve