Debian Linux Mint F.lux error quick fix. Sometimes, F.lux will not automatically start in your Debian systems. It also, happened to me. So, what i did was manually setting the f.lux configuration and adding it to the startup program.
xflux must be installed on your system. To test this, open a terminal and type the following command. If it is working and then add it to the startup application. In this way, f.lux will be automatically started.
Add the following command to the startup applications :
xflux -l 0 -g 0 -k 5000