Windows 8 and 8.1 Forums


Windows Defender running high CPU when system idle ...

  1. #1


    Posts : 2
    Windows 8 (64bit)

    Windows Defender running high CPU when system idle ...


    After around 5 minutes of my system sitting idle, MsMpEng.exe kicks in running about 50% CPU and keeps running until I start using my laptop again. I have no idea what it's doing. Or how to stop it doing it. Has anyone come across this problem before? If so, any ideas for a fix?

    Many thanks ...

      My System SpecsSystem Spec

  2. #2


    bangalore
    Posts : 634
    Windows 8.1 professional x64 + WMC


    When your system is idle it performs the automatic maintenance(defender performing a quick scan, de fragmentation etc)

    Nothing to worry
      My System SpecsSystem Spec

  3. #3


    india
    Posts : 101
    Windows 8 pro with WMC x86 & windows Blue preview x86 with Windows 7 Ultimate SP1


    it may be that you might have scheduled a full system scan, which makes it use CPU more. so verify that you haven't scheduled a scan i can't help out more because i haven't been windows defender user for much time .
      My System SpecsSystem Spec

Windows Defender running high CPU when system idle ...
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