I'm on a 2020 MBP (2.3 GHz Quad-Core Intel Core i7 processor; Intel Iris Plus Graphics 1536 MB) running Tahoe 26.2, though f.lux stopped working with Tahoe 26.0. I use multiple "desktops" (maybe called "Spaces"? now).

I disabled "Automatically Adjust Brightness" as suggested in earlier posts. Now f.lux works (if I restart it) UNTIL I switch desktops. Then it stops working again. Returning to the desktop on which I started it, does not bring it back, even for that desktop.

I also verified that Night Shift was off and not causing conflicts.

Any suggestions? I really miss the f.lux functionality.

If you are going to suggest I report any of this to Apple via their feedback form, what category do I submit it under? What should I tell them?

Thanks!

On newer Apple Silicon macs, there is no switch (since there is just one GPU) and so we don't have to build a profile to keep things working. It's better in most cases for f.lux to be a "temporary" effect. But in case you somehow wanted the old behavior, it might still work with a pref - check out: https://justgetflux.com/news/2014/10/28/profile.html

it works

As of "public beta 2" (developer beta 5 on Aug 5, 2025), this bug is fixed.

If you have an older beta please update to use f.lux, and you can enable automatic brightness as you like.

As of beta 4 (public beta, July 24, 2025), we know that "Automatically Adjust Brightness" and the color controls f.lux uses are not working together, on modern MBPs at least. You might see a MacBook Pro with no changes to screen colors on an internal screen, but with working colors on an external screen.

For now, the main workaround is to disable Automatic Brightness using Settings > Displays > Automatically Adjust Brightness. We hope this will be fixed before the beta is over (it was reported to Apple about a month ago) and we are looking for workarounds in case that does not happen quickly.

I've been using this software for over 10 years now and honestly can't do without it. In the meantime I've applied @bobby's workaround and it's doing the job for now.

Thank you for all your work on this.

When you switch tabs, you are adjusting what the screen will look like in the future, not right now. If you want to adjust what the screen looks like right now, you don't have to change tabs, they will change automatically throughout the day and all you have to do is move the slider.

Possible solutions:

• Add a 'Custom Profiles' feature to f.lux so that I can quickly select a custom profile from the f.lux menu bar icon (eg "Jamie's Profile - Game Mode", which sets color temperature to 5200K).
• Add an option to f.lux preferences to set a specific color temperature for 'disabled apps' list (rather than disabling f.lux completely). Eg use 5200K for all 'disabled apps'.
• Allow f.lux to be controlled via macOS Shortcuts app. This way I can simply fire off a custom shortcut that sets the current color temperature to 5200K (eg "Game Mode" shortcut, which sets flux temperature, dims my Hue lights, etc).
• Allow f.lux to be manually controlled via scripting (eg AppleScript, CLI tool, etc)

A CLI tool would be super powerful as it gives full control over f.lux via scripts. For example I could run from my terminal (or shell script) - flux temp 5200, flux daytime, flux disable, etc.

Any of the above options would work and really set f.lux apart from Night Shift! I would pay for a 'f.lux Pro' for such features 🙂

I found a discarded LG Flatron E2260, not the most recent monitor, but functional enough. Long story short, it turned out to be a classical case of dead capacitors.

However, even if colours are OK relative to one another, compared to the built-in LCD, they're still very blue (test made with calibrated internal LCD and f.lux disabled). Worse, f.lux doesn't appear to have any influence on the colour balance when I do turn it on.

The built-in monitor menu is still very limited: preset temp colour can either be sRGB, 6500K, 7500K, 8500K, 9300K, plus three gamma levels. Of course there's a manual option to adjust all three primary colours relative to one another. I don't know how to do that properly, though.

Any help appreciates

Is there something I can do to fix this so the screen doesn't flash?

Thanks very much in advance for any and all help! Much appreciated.

HUGE fan of using Shift+Page up/down on my windows f.lux to increase/decrease brightness, but just got a mac and am struggling to find anything online about why it's not an option on mac. I can adjust the brightness on the mac itself, but it doesnt do anything for my two external monitors

Any help is appreciated, have been losing my mind over this lately :)

There should be an icon in the menubar

We've updated the website to point to 42.2, so builds going forward will have proper signatures.

Also, we did make an update a few years ago to support DCI-P3 displays (like the new Macbooks), so make sure your f.lux build is up to date also.

I'd much rather be able to say "at 7pm, start warming the screen" rather than have it based off sunset.

I really like what flux does but I need it to be more customizable.