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f.lux on macOS

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f.lux on Windows

General questions

f.lux on Windows (2013 version)

  • I work nights. How do I flip the day and night settings?
    PC f.lux users can unlock the color temperature sliders by holding down the control key while setting your temperature, so night can be swapped with day. We're working on a feature that lets you control time settings more closely.


    • f.lux doesn't work on Windows 10. Help?
      Immediately after upgrading to Windows 10, many machines are using a basic video driver that does not work with f.lux. Windows Update will usually get a better driver (within a day) to a version that works with f.lux. In some cases this does work on its own, so we recommend that you update your drivers with the manufacturer's latest version.
    • I installed f.lux but I can't see any change.
      Is it past your local sunset time? Just wait, and f.lux will kick in at sunset.
      Is your location set correctly under Settings?
      Check that your night-time settings are not set to Daylight.
    • I uninstalled f.lux and my computer is still orange, what gives?
      Some users have encountered a problem where f.lux is no longer running but the screen still appears tinted. If you have checked the Processes tab in Task Manager and there is no f.lux process present, this means another program has absorbed the f.lux color profile. The workaround to restore your screen to its normal profile is as follows: Reinstall f.lux. In the Settings Menu, set both the Night and Daytime sliders to daylight. After 24 hours, any other programs should have re-absorbed the new profile, and you may uninstall f.lux with no more changed colors.
    • F.lux makes my mouse stutter, makes my computer slow, or it doesn't seem to change my colors at all.
      Most problems like this can be fixed by updating your video drivers.
      Try one of these links: NVIDIA drivers, AMD Radeon drivers, Intel drivers.
    • Uh oh, my Surface Pro 3 is freezing! (or my Intel-based laptop is slow with f.lux).

      Early-2014 Intel HD Windows 8.1 drivers have some bugs that give problems with f.lux, and you may not have the latest one (Surface Pro 3 does not as of September 2014). To make sure you have the latest:

      1. Run Device Manager and navigate to Display Adapters : Intel HD Graphics Family. Pick the "Driver" Tab.
      2. Check which version you have. If it's less than, you'll want to update (the early-2014 drivers that end with "3412" up to "3621" can cause slowdowns and crashes with f.lux).
      3. Download a new intel driver here: Intel HD drivers
        If using a "standard" Intel video card, just get the EXE and install it. You're done!
        If using a Surface Pro 3 or "customized" OEM driver, pick the ZIP download so we can force the install.
      4. If you picked the ZIP, unzip it and then:
        1. Back in Device Manager, click "Update Driver" and "Browse my computer..."
        2. Choose the Downloads folder and the zip folder you just extracted.
        3. If Windows refuses this new driver, you should Uninstall and Delete the existing driver and start again from step #1. Windows will use its basic driver in the interim (you won't be without video.)
    • Ok, but CCC.exe on my AMD Radeon card is still using 1% CPU all the time, and I don't want that.

      The Catalyst Control Center is an optional component that can be uninstalled, and you might consider doing this if you're not frequently adjusting your settings for gaming or other reasons. Use Add/Remove Programs, and choose "AMD Catalyst Install Manager" to proceed.
      Do not uninstall the Install Manager, but instead use it to uninstall Catalyst Control Center. In our test, this didn't even require a reboot. Also, leave a note on this page (with the driver version) so we can report it to AMD.

    • My Macbook Pro is having trouble with f.lux, and it flashes sometimes.
      On dual-GPU machines we write an ICC profile in order to make the "switch" between video cards more seamless. In some older machines, and every so often, this doesn't work so well. To read about how this system works and turn it off if you want, check out our description here:
      Notes about f.lux changes to ICC profiles.
      If your Macbook is crashing due to switching between cards, or just to understand when it happens, a really great workaround is to download gfxCardStatus and use only one of the two video cards.
    • My computer flickers when I use Parallels. What should I do?
      You can disable "use Windows gamma settings", and directions are in this post.
    • I use Shades on my Mac, and f.lux is fighting with it.
      Users have reported flashing and flickering when using these together. We recommend you only use one of these programs at a time.
    • I can't drag the program to the Trash on my Mac.
      First quit f.lux from the Settings menu, to the left of your system clock.
    • I adjusted my color / gamma settings using Windows "Calibrate Display" or NVIDIA's controls and f.lux removes them. Can you keep these settings and use f.lux?
      Unfortunately, these systems do not write their settings in a format that f.lux can access (we read VCGT headers only). For better results, we recommend the use of hardware calibrators such as the very good x-rite i1 Display or ColorMunki Display, which write settings in standard ICC files that f.lux can read. If you don't have access to a device like this, you might find a suitable profile for your display online at the TFT Central Monitor Settings Database.

      Several people have reported that QuickGamma works well and produces good profiles that f.lux can read.

      If you use a Spyder, the software profile loader may cause f.lux to flash periodically. You can disable the Spyder software on startup, and use f.lux instead to load the profile. Also, when you're calibrating a display, you'll want to do the opposite and quit f.lux before you do.

    • My ASUS laptop is flickering for a minute after startup.
      See if you can find an "ASUS Splendid Video Enhancement" feature and uninstall it.
    • My Sony VAIO is flashing every time it wakes up.
      See if you can find a "Color Mode Setting" in Vaio Control Center > Display, and change it to "Do not apply color mode".
    • I have a new tablet (e.g., a Dell Latitude 10 or an ATIV 500T) that does nothing when I run f.lux. Is there a way to make f.lux work?
      These Atom-based machines use the PowerVR SGX545, a mobile-class video card that doesn't currently support color controls. We've had many reports of failures with this chipset, so right now we don't anticipate a better result.
    • I have a DisplayLink USB monitor adapter. Is there a way to make f.lux work for this display?
      DisplayLink has no support for color calibration, so f.lux can't make changes to DisplayLink monitors. Unfortunately, you can only use f.lux today on displays that are directly connected to your computer. (e.g., it usually won't work over remote desktop either.)
    • Since upgrading to Windows 10 Anniversary, my non-DisplayLink screen is flashing a lot, but only when I have my USB monitor or docking station plugged in
      Yes, we had a bug that caused this and the main build has been updated (v3.12). Please get an updated build here.
    • My PC's Anti-Virus program flagged f.lux as malware.
      As long as you've downloaded f.lux from this site, you don't have any malware. Every once in a while we get flagged as a potential threat due to the nature of our installer and updater. If this happens to you, please send us a note with your anti-virus program and details and we will contact them for review.
    • Something else is going wrong with f.lux for Windows
      We always recommend updating video drivers as a first line of defense. If you're experiencing flickering or problems, please upgrade your drivers. If that doesn't work, we love to fix bugs. Please send us a note with information on your operating system, video card, and any other information that might be helpful to us.
    • iOS: Why do I need Location Services enabled?
      f.lux uses Location Services to determine the time of your local sunrise and sunset. In the future we will include an option to choose times manually.
    • Why isn't f.lux available in the Apple App Store? I don't want to / can't jailbreak my device.
      We would love to make f.lux available for all iOS devices. To make f.lux work on iOS, we've had to go outside the bounds of what apps are normally allowed to do. Currently, iOS does not allow developers to access the Private APIs we need to make f.lux work on iOS.
      Apple values their customers' feedback, so if you have a minute to let them know how f.lux has helped you, and that you'd like to see it available for all iOS devices, send a note at iPhone feedback or iPad feedback.
    • When is the Android version coming out?
      f.lux on Android requires a rooted phone, but it's on the play store here.

    More questions

    • Plenty of things already change the brightness of my screen. Why is this different?
      f.lux changes the color temperature of your display. Natural light is more blue, while most artificial light (including candlelight) is warmer. Incandescent bulbs, which we're all used to, become more red in tone when you dim them. But newer LEDs and CFLs don't - this includes the backlight on your monitor. If you're a photographer, you've probably dealt with this, since pictures taken inside at night are always much more brown than photos outside.
    • Isn't this exactly the same as the Macbook ambient light sensor?
      No, though they do work together nicely. The ambient light sensor measures the brightness of the light in your room and adjusts the brightness of your screen based on that. f.lux changes the color of your screen and warms it up according to the type of light you're using and the time of day. f.lux doesn't use ambient brightness to adjust colors. You might be in a dark room with very cool light, you wouldn't really want your monitor to look warm, but you would want your display to look dimmer. We've found that when your screen colors match the color of your ambient light correctly, you don't need to adjust monitor brightness as much.
    • What is color temperature, exactly?
      The term color temperature is a way to numerically describe how much red or blue light is illuminating a room. Color temperature is measured in Kelvins, and is determined by the kind of light you're using. Confusingly, warmer (more red) light sources are described in lower degrees Kelvin. Compared to indoor lighting, daylight is cool - very blue. A candle is around 1800K, while a sunny day might be 6000K. An overcast day is more blue, so it might be around 7000K.
      Most computer monitors display around 6500K. If you are using incandescent task lights behind your computer, those are around 3000K.
    • I'm a designer / photographer / artist so I can't use f.lux. This isn't for me!
      f.lux was created by people who care a lot about accuracy in colors. We know you want to make sure your colors are perfect so there is an option to disable f.lux for 1 hour at a time (for example, while using Photoshop). This setting returns your screen to its normal settings. In the future we plan to allow automatic disabling of f.lux when you launch certain programs. f.lux is not designed for use during advanced color work, but it's fine for layout or HTML.

    Installing & Uninstalling

    Windows Install

    1. Click the f.lux Windows download link.
    2. Run the installer and the f.lux settings page will appear.
    3. Enter your location and select the type of lighting in your room at night.

    Windows Uninstall

    1. If you find flux.exe running and do not want it:
    2. Go to the Start Menu > Add/Remove Programs > Uninstall f.lux

    Mac Install

    1. Click the f.lux Mac download link.
    2. Click the zip file to expand it
    3. Double click the "Flux" application in your Finder window.
    4. Enter your location, set your wake time, and select the type of lighting in your room at night.

    Mac Uninstall

    1. Go to the f.lux Settings panel (to the left of your system clock)
    2. Choose "Quit f.lux"
    3. In Finder, select and delete the f.lux app, and empty the trash.

      If you still have a tinted screen, keep going with these instructions until things improve:

    4. In System Preferences > Displays > Color, delete the "f.lux profile" (if f.lux was force-quit)
    5. Reboot the system
    6. Disable automatic brightness, reboot, and turn automatic brightness back on


    Ubuntu-inside.me has written a great guide to using f.lux:

    Note: The ubuntu-inside.me site has disappeared but thankfully Archive.org maintains a mirror (linked above) with the original information.

    Want to contact us? Email support@justgetflux.com.