Hello,
I don't know if it is written somewhere but when I wanted to launch client from source on windows 10 (python src) after installing everything, I had the message "failed to get uid something".
I finally discovered after a few hours that the exe was not found (after breaking everything and showing messages in the source code)..
So if you want to dev on windows and have this message, be sure that "faf-uid.exe" is present in lib folder, if not download it (fast way is copy it from the faforever you downloaded to play games and paste it)
I don't know if it is the good location but just wanted to have a trace somewhere about that.