Can't Find "cnmss" followed by screen flickering.

  • Background: In addition to the 1920x1080 display within the laptop I have (ASUS ROG G752VL-DH71), I have an external HP Compaq LE2202x screen of the same resolution. It runs Windows 10 Pro (build 15063 Creator's Update) at 64-bit. I also have Task Manager's Startup tab entry for Flux 3.10 enabled.

    After logging in, I am at first greeted with a regular looking display. After a couple of seconds though a dialog box error message appears saying it can't find "C:\Users<USER_NAME>\cnmss" and then the primary screen attached to the laptop starts flickering between the default color and the f.lux color setting.

    Rather confused, I assumed it was a problem with buggy NVIDIA drivers at first (the computer I use has a 965M GeForce GTX GPU). Hence, I booted into safe mode to uninstall and reinstall the newest drivers. When I start it up in safe mode, this issue does not happen. Most likely because f.lux does not run in safe mode. I also disconnected the external monitor, used another external monitor, etc. But the flickering on my primary screen continued. Finally, I remembered that f.lux is also controlling some of my screen's settings, so I exited the application. It stopped.

    To be very sure, I restarted and then re-exited the f.lux application. This did wonders, immediately stopping the rapid color flickering that had been happening before that. I then uninstalled the application, and the problem hasn't returned since.

    Please consider a hotfix in the upcoming versions for this issue.

  • Hi - yes we fixed issues with docking stations in 3.12 last year. Sorry we didn't push an update to everyone.

    Meanwhile, we have released a new version at that fixes this and many more issues.

    (cnmss appears to be unrelated, maybe a Canon printer driver.)

  • @herf Ok I will try again soon with the newest version I can find on this site.

    And yes, looks like cnmss is unrelated. Apologies. (

    I will update after I reinstall the new version of the app. Thank you.