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MsMpEng
MsMpEng.exe (Microsoft Security Essentials) has suddenly / recently been using a lot of CPU time, to the point that performance is lagging (Win 7 Pro+SP1), especially for IE11.
If I open MSE control panel and turn off real time protection, CPU usage drops. I can turn real time protection back on as soon as CPU usage drops, and things are ok for a while...
Don't have any MSE scans scheduled so only real time scanning is active.
I've seen posts suggesting to add C:\Program Files\Microsoft Security Client\MsMpEng.exe to the list of excluded files and locations as the fix for this. I would think this should only have any effect during an actual scan, but not during "real time protection".
SAS and MSE don't find any malware so I don't believe that's the problem. And MSE is fully up to date.
Thoughts and Ideas?
RoHe
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February 5th, 2015 18:00
OK, just did a little test.
Opened Device Manager with no other apps running (aside from Windows and background drivers) with WU off. CPU usage was 0-2%. So I set WU to check but not install and CPU usage went up to 50-75% instantly and stayed up there. After I opened IE11, CPU usage pegged at 100%.
Turned WU off and CPU usage went back to 0-2% and only to 7-15% with IE11 running.
So I have to conclude -at least here- WU is causing some of the problem. I'll leave it set to never and I don't think it hurts to leave MsMpEng,exe in the excluded zone, unless somebody can tell me if there's a reason to think otherwise.
THANKS!
joe53
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February 4th, 2015 17:00
Hi Ron:
You hi-light a problem that has dogged MSE for years, with no definitive solution. I used MSE for years without seeing this bug - until one day it appeared. When I found no quick solution, I switched to Panda Free AV. (I have little patience for grief like this). This was about 2 years ago.
I found the following suggestions to solve this MSE problem,
How to fix MsMpEng.exe High CPU Usage problem
www.wintips.org/how-to-fix-msmpeng-exe-high-cpu-usage-problem
from a post that is less than a year old. I can't vouch for any of the solutions, but they seem reasonable.
RoHe
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February 5th, 2015 11:00
Seems like it only became a problem earlier this week - for unknown reasons. There were a number of MSE update this week so I wonder if one of them caused this. They're all listed as "successful" in the update history.
I added MsMpEng.exe to the "excluded" list as was suggested at some of those links. And, I turned off Windows updates. I had WU set to check/notify but not to install. So now it won't even check unless I do it manually. Not a problem for me...
So far, that seems to have fixed the issue. MsMpEng.exe is down to ~0-2% CPU usage now. Not sure whether one or both of those changes were needed to fix this so I may have to play around to see if I can turn notification back on as long as MsMpEng is on the excluded list, or vice versa.
The joys of Windows... :emotion-12:
joe53
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February 5th, 2015 12:00
Thanks for the feedback.
I doubt it was WU that was responsible, since I have always kept it entirely turned off on all my systems, and I still saw that bug. And the idea of adding an AV executable to its own exclusion list seems odd, but has obviously solved the problem for some, including (perhaps) you.
I still like MSE, and find it appeals to 2 distinct groups:
1) Those with minimal computer or security savvy, who would otherwise be unprotected.
2) Those with considerable computer and security savvy, who know how to compensate for MSE's lower baseline protection rates (not that 80% real-time protection is shabby), using additional programs/strategies.
Those falling between these 2 categories tend to focus on controlled lab testing to choose their AV.
I think it's time I gave MSE another try on a secondary PC.
RoHe
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February 5th, 2015 18:00
Well, who knows... Just because you had WU turned off and still had the problem doesn't mean it wasn't causing it here.
In all the years I've used MSE with XP Pro and now Win 7 Pro, I never had this issue until now, so I'm open to any and all of the above being part of the problem.
That said, since I made both those changes, I haven't had a single slowdown caused by CPU usage hitting 100% and not a single lag or freeze with IE11 [knock on wood! :emotion-4: ].
Time will tell... :emotion-60:
joe53
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February 6th, 2015 14:00
Follow-up:
It turns out that my netbook experiencing slowdowns due to MsMpEng.exe hogging the CPU did, in fact, have WU configured for automatic downloads. This is something I would never have authorised, so I suspect MS pulled a fast one on me somewhere. Thanks Ron, for sticking to your guns about this.
Anyways, MSE is re-installed on this Win 7 Pro/SP1, WU is fully disabled, and MsMpEng is excluded.
MSE works as well as ever. So far, no CPU slowdowns in Task Manager ...
RoHe
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February 6th, 2015 16:00
Isn't this fun? NOT!