We don't know of any updates in High Sierra that should affect this - did you add any hardware/external displays or anything like that.

Usually this means you need to set your location from the f.lux preferences menu.

I believe Linux has the same problem. I don't know if f.lux has a Linux version or not, but I use a similar program called redshift, and it has this mouse pointer issue. The little bit of research I did indicated that it is a very difficult problem to fix, so I just live with it. A minor annoyance.

Also started flickering here, not sure if related but quite recently upgraded to macOS 11.4.

Macbook pro 13" 2017
External monitor: Eizo EV2436W

Both monitors, the macbook one and the external monitor are flickering synchronously.

We ask the system about the installed profile for each display and try to use the profile correctly. So in our tests here, with a Thunderbolt display (standard gamut) and a Macbook (wide gamut) the two look identical, because we use different transforms for each display.

Is it possible that the external display is actually wide gamut, but macOS does not know about this? If this were true you may see other apps displaying colors that were extra saturated, and the fix would be to install a good ICC profile for the external display.

@ralvydc Just tested Gradual Transition and it appears to start the Transition 1 hour before the target time. So if my Bedtime is 9pm (9 hours before my WakeUp time of 6am), with Gradual Transitions set, f.lux starts decreasing blue light at about 8pm, taking 1 hour to get to my Bedtime setting. Perfect.

Thanks for the quick support.

[EDIT/UPDATE]
Confirming it is the company's security software killing f.lux, nothing on f.lux's end. Appreciate your looking into it! This thread can be closed, or removed.

@Gonzalo hi Gonzalo - can you post in our Windows forum with f.lux options > driver info?

A bit more information
Graphics:

Radeon Pro 450 2 GB Intel HD Graphics 530 1536 MB

OK, I can understand why a two week delay works best for you, but now it's been over four weeks. I have 41.4 but heard that 41.5 is out now and it still tells me I 40.1 is latest. Are you still fighting with bugs in 41.x?

I had this issue too, unfortunately you cannot set your own sunset, or even better would be just pick times when you want the brightness to change! Only 3 changes would be fine like we have currently, but more would be great.

Anyways, I found a workaround that works for me. I have sensitive eyes so I like it to start getting dimmer as it is getting dark but not yet "sunset" and then even dimmer later.

I achieved this by setting the Bedtime color to be the highest at 5000K, then the Sunset to be "Incandescent" and the Daytime to be 3300K. Then I set my earliest wakeup time to 7:00 PM. By doing this I was able to adjust the graphs to something that works for me. You can set a slider to be higher than the slider above it by holding Control while you move it.

Just play around with it and I am sure you can find a setting that works for you!

Sorry to hear this - can you install again from the website?

https://justgetflux.com/

catalina and 10.15.7