5 Replies Latest reply on Feb 14, 2018 4:41 AM by Diko.bg

    MsMpEng.exe tremendously slowing LR

    Diko.bg Level 1

      Hi everyone.


      Just wanted to inform you about weird glitch. My Windows Defender (WD). The process/file name MsMpEng.exe began utilizing constantly about 12% CPU (i7-6700K). Couldn't use LR (6.9) at all. Any operation (e.g. spot removal or even next picture view) would take up to 3 minutes. The weird thing is that WD did not slow down my system (Win 10x64). I hardly recognized that WD is active all the time after thorough investigation. Thought it is just another scan, which however was not the case even after disabling the WD real-time protection.



      After researching the possibility for infection and found no infection (kind of have been in AV field for some time so know a few tricks) I checked and found that

      • the WD program folder must be excluded. C:\Windows\Windows Defender\ or C:\Program Files\Windows Defender\
      • As well as some false positives I am aware of (a few hacking tools, for which I never have the time to test).
      • Restart & observe if MsMpEng.exe is still using CPU without stopping. If not - check if LR slowdown is rectified.


      Do NOT:

      • Stop WD permanently - unless planning to install some serious alternative protection
      • Edit any registry files - as long as you are sure about your files


      Why and how did this happen?

      Simply all began after another Win update.


      I write this for anyone that might experience the same problem.