Highlights

Thursday, September 20, 2012

SOLVED! - High CPU Usage of Microsoft Security Essentials

I've at least two laptops, after installing Microsoft Security Essentials, the CPU usage jumps up. Stopping or uninstalling it resolved the problem, which isolated the source to be Microsoft Security Essentials itself. After some research, this works for me as a workaround this problem.


  1. Run Task Manager, find the process with high CPU usage. (Sorting by CPU may help you find it)
  2. Likely you will find "MsMpEng.exe" has taken much of your CPU time
  3. Now go to  your Microsoft Security Essentials, click on the "Settings" tab. Select "Excluded files and locations"
  4. Browse to "C:\Program Files\Microsoft Security Client\MsMpEng.exe", Ok and press Add button to add the file to your list of excluded files and locations. Press Save changes button.

Same method applies to other trusted files. You should see the CPU usage drops down dramatically.

41 comments:

  1. thank you jack. youre a lifesaver.

    ReplyDelete
  2. LOL! It's busy scanning itself.

    Thank you for the fix, it worked a treat

    ReplyDelete
  3. UnBloodyBelievable! Literally choking on itself!!

    ReplyDelete
  4. Just fixed my problem, thank you!

    ReplyDelete
  5. A million thanks, I had been struggling with this issue for a while (laptop was almost unusable)

    ReplyDelete
  6. Legend! There must be millions with this issue, what a joke.

    ReplyDelete
  7. same problem windows 8.1 fixed now thanks heaps

    ReplyDelete
  8. Wow. I wondered what was causing my system to go into a regular tailspin with nothing visibly going on. Grrrr. Thanks for the tip!

    ReplyDelete
  9. AMAZING! Restarted after doing so and 100% to 2!!!

    ReplyDelete
  10. Thanks so much. This was great on a server of ours that was running very slow.

    ReplyDelete
  11. thanks that worked :)

    ReplyDelete
  12. you should be in charge of MS.

    ReplyDelete
  13. Thank you so much !
    Wonder if Papa MS knows about it ??

    ReplyDelete
  14. Wow!, worth millions!!
    Apply.
    Thnx.

    ReplyDelete
  15. Gracias, gracias, gracias!!!

    ReplyDelete
  16. very nice, mate.
    I opened MSE and clicked on its options.. the cpu usage at task manager was showing 12, 16...
    after this procedure, it stays on 2 or 3 only!
    excelent, thanks a lot

    ReplyDelete
  17. Mine was 55 now 5 :D such a great solution, you deserve a medal or something :)
    anyway, thanks a bunch man!

    ReplyDelete
  18. A real solution! Thanks a lot!!!

    ReplyDelete
  19. This solution WORKS ! ! ! So why can't Microsoft 1) just say so and 2) do a proper update to resolve this problem ? ? ?

    ReplyDelete
  20. @Anonymous
    1) They will never
    2) Now they will.

    ReplyDelete
  21. Thank you! This was dragging down my Citrix servers horribly!

    ReplyDelete
  22. Thanks. In Windows 8, I found the file under Program Files\Windows Defender

    ReplyDelete
  23. Awesome! Thank you!!

    ReplyDelete
  24. Thank you very much, works perfect. Couldn't emagine scanning itself. what a bug!

    ReplyDelete
  25. Been driving me mad for months thanks very much for that!

    ReplyDelete
  26. Vy nice post ... thanks...

    ReplyDelete
  27. WAY TO GO!!!!
    The classic feedback loop.

    ReplyDelete
  28. Dear God. This has been pissing me off for years on several WinXP & Win7 installs. Always ended up in forums (including microsoft professional coders who worked on MSE & related projects) that discussed it to death without ever realizing it was recursively scanning itself. The idiocy of microsoft knows no depth; clearly it's turtles all the way down.

    Thank you!

    ReplyDelete
  29. In my case MsMpEng.exe was hogging the disk i/o keeping other programs from accessing the drives in a timely manor. 100,000(s) picture files. Disabling this process seems to have vastly increase overall performance.

    ReplyDelete
  30. Thanks indeed. Refreshing to be given a solution that works for once.

    ReplyDelete
  31. an actual solution rather than a thousand noob suggestions...thank you!

    ReplyDelete
  32. Thank you to the OP!! This gave me the info needed to do the same for Windows 8.1. Incase people are on Windows 8/8.1, click Start and Search for Defender (Name of Windows Security Essentials). Then follow the instructions but add the following path instead:

    C:\Windows\WinSxS

    ReplyDelete
  33. Wonderful! Worked immediately. Thank you very much.

    ReplyDelete
  34. Great job. What exactly happens when this antimalware service executable, aka msmpeng.exe, when it is put on an exclusionary list within it's own program? AVG resident shield service is using slightly more than this anyways. And Firefox seems to be my most notable resource drain. 15 years later, and I'm finally getting tired of this nonsense. I'm moving back to pen, paper, and rotary phones. LOL! Yes, I am serious. / Thanks again for having a comment board without requiring logins. Comments boards which require logins are a waste of friggin time.

    ReplyDelete