If you have a newly installed Firefox on a newly installed DragonFly system, you might be unable to load your Firefox account on first load, like in this screenshot. A workaround is to load your profile on a different machine and copy it over. My guess is permissions for profile creation, but that’s just a guess.
A running description of activity related to DragonFly BSD.
That’s an issue I have encountered at least since 5.4. However this workaround didn’t work for me. Firefox on DragonFly has been ignoring the profile and creating a different one instead.