After update performance issue with certain PCs RRS feed

  • General discussion

  • Over the past 2 months there was an update to the Forefront Client that caused a strange issue on some of our machines.  Basically when we update device drivers MsMpEng.exe goes nuts and uses at least 50% to 98% of the CPU for the entire duration of the driver install/update.  

    The immediate result is that some of the larger device driver installs (like video drivers) actually time out because of this.  Using procmon I traced the cause of the delay. It looks like MsMpEng is scanning the setupapi.dev.log file over and over and over..hundreds..maybe thousands of times.  We noticed that if we turned off logging for the device driver udpate/install and app install logging that this issue disappears.  We've had this level of logging for years and only in the past 2 months or so has this issue started to pop up.  The setupapi.dev.log file is rather large and so I can see why it's causing a delay if it has to scan the file over and over and over.

    We aren't sure what changed.  We used an older image that had an older version of the Forefront client installed and we made sure it didn't update to a newer client version.  That version of forefront had no issue with device drivers timing out. After updating the client we now have the issue. A change was made recently and we believe the forefront client is behaving differently.  

    Any ideas about what could cause this?


    • Changed type Susie Long Tuesday, April 8, 2014 2:59 AM
    Tuesday, March 25, 2014 11:41 AM

All replies

  • Hi,

    Thanks for your question.

    How did you perform the update of Forefront Client Security, from windows update or manually? In addition, what are the editions of the Forefront Client Security now and before you updated?

    Best regards,


    Friday, March 28, 2014 6:19 AM