f.lux prevents computer tower from entering sleep mode

  • Since f.lux updated to v4, I have been having issues with my computer going into sleep mode. I assumed it was some other program, so I did a diagnostics in command prompt, and it pointed to f.lux as being the source of the issue. I exited f.lux and manually put my computer into sleep mode, and it worked. I turned f.lux back on, and it did the same thing. Why is this preventing my computer from going into sleep mode?

  • We are keeping the machine alive if you enable Philips Hue support.

    We have to keep a constant connection to the bridge to make our schedule work.

    But even so we should show in the UI that we are doing that so you can turn it off.

  • So I have to turn it off any time I want my computer to go into hibernation?

  • The feature requires a dedicated machine right now, or otherwise the lights stop responding to the schedule.

    Do you want your lights to adjust only when the laptop is on?

  • It's my desktop. I just find it odd, because my computer would still go to sleep with previous versions of f.lux.

  • Yes I agree... I hope we can find a better way to do this in the future. I can absolutely make it more clear what's going on, but I would be hesitant to do something that "breaks" when your machine goes to sleep.

    Right now Hue only works if we are constantly looking for new bulbs to come online.

    It is disappointing that there is no great "app platform" with <1W devices that stay on all the time (like raspberry pi, or even Amazon Echo) - on mobile and desktop is power managing away "always on". So we're asking your PC to do something that should be much more lightweight.

    If you never power the Hue lights off with a lightswitch, we may be able to make the bridge do most of the work (but its schedules don't quite match f.lux).

    FWIW, we do go into the lowest power mode possible, so your screen should at least sleep. My PC uses about 40W this way, which is still too much....

  • Hey, I know this topic is a bit old but I ran into the same issue today and I would like to share this "fix" I found for anyone who follows.
    To block f.lux from keeping the PC awake, but still allow it to control your Hue lights when the PC is on, open a command prompt window in administrator mode by opening the search bar (Windows 10), searching for "command" and right clicking the command prompt and selecting "Run as administrator". Next, in the command window, type these two commands (confirm each by pressing enter):
    powercfg /requestsoverride PROCESS flux.exe SYSTEM
    powercfg /requestsoverride PROCESS flux.exe AWAYMODE

    After that, f.lux should no longer prevent your PC from entering sleep mode.

    Hope this helps!

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