EDR: Excessive Event Loss at System Reboot
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EDR: Excessive Event Loss at System Reboot


Article ID: 285953


Updated On:


Carbon Black EDR (formerly Cb Response)


  • An EDR Windows Sensor is showing "Excessive Event Loss" in the web console
  • The message disappears shortly after reboot


  • EDR Sensor: All Versions
  • Microsoft Windows: All Supported Versions


The sensor driver event queue is being filled by a large number of Windows startup events before the sensor service starts


  1. Make sure that AV exclusions are in place EDR: Which Sensor directories need exclusion from 3rd party anti-virus scans?
  2. After a couple of check-ins from the sensors the message will go away

Additional Information

  • Kernel Queue is hard coded to 12k for all OS's. By considering physical memory size on the box this value can be higher, resulting in the kernel not dropping events.
  • At start, the kernel queue caches events before the user level service can start
  • Excessive event loss can also be seen
    • If event types have been disabled in the sensor group
    • If the sensor service is not running at all. Run sc query carbonblack in cmd to confirm