MacOS Catalina Bug



  • Flux doesn't seem to work on latest Catalina OS. After turning it on, it flashes and colors/temp looks weird.


  • f.lux team

    Which hardware are you using?
    Also do you have access to the Feedback Assistant (beta or developer)?



  • The same problem.
    MacBook Pro (15-inch, 2018)


  • f.lux team

    Anyone reading this: if you have Feedback Assistant, please send a report to Apple (we can't report it otherwise).

    For general troubleshooting:

    1. Try disabling automatic brightness - does it help?
    2. Try disabling automatic GPU switching if you have two GPUs


  • Can confirm - I have the same problem. (Macbook Pro 13 inch, 2018).

    This device does not feature a second GPU.
    Disabling automatic brightness does not fix the behavior (looks the same).



  • @testesttest8889 I confirm, Flux doesn't work correctly on my MacBook Pro 13-inch 2019 with Catalina OS. It flash and look very weird... Closing flux and everything return to normal...


  • f.lux team

    Can someone also test turning off True Tone? A conflict there would make sense, since it's only on the newer models.



  • 2018 MacBook Pro 13-inch with Catalina OS and True Tone off still causes the flashing and colors/temp to look off



  • Yep, True Tone is disabled.



  • Same issue here. Flux also causes OSX to prompt to grant screen recording permissions. I suspect the latter is just due to the API it uses, but perhaps failing to grant it is what's causing the problem?


  • f.lux team

    This should only be in the about box, which we use to estimate screen brightness. Could add a button you'd have to push if it's too alarming.



  • F.lux didn't work for me either when I installed Catalina, but when I ticked "true tone" box it started working normally again.


  • f.lux team

    Anyone with "Feedback Assistant" please send a note to Apple for us?

    Has to be done on a machine that's affected, and we haven't bought a new MBP yet. :)



  • Just a small report from me - everything works now. I haven't changed anything nor updated something, yet it started to work normally again. Maybe this is only in the first few hours after upgrading?


  • f.lux team

    @_paul Okay so maybe this is a True tone conflict, it just takes some time to actually turn off?



  • Still experiencing same problem, turning of True Tone/Auto Brightness didn't help



  • For me it works when my external display is plugged in. As soon as I unplug it everything starts flickering and the color filter is only showing around the UI elements, on and off.

    As other mentioned, True tone and auto brightness don't change a thing.



  • Just for the record, I highly doubt this issue is related to f.lux. As far as I can tell, f.lux is simply feeding a color profile to macOS, and there seems to be a general color profile issue going on in Catalina.

    I have custom monitor calibration profiles (from a calibration device), and macOS randomly ignored the profile. As far as I can tell, most of the time, macOS decides to apply the color profile correctly for everything except for pure white. #fff is always rendered as #fff, even though the color profile might tint it differently. In f.lux, this is especially harsh since everything white will glow really bright next to the red'ish colors.

    I have reported several issues in regards to color profiles in Catalina via the Feedback Assistant.