Dropbox was hung on connecting. Previously it was working fine. I was using Arch Linux, Gnome desktop. For a long time I couldn't find a solution. I was looking for a problem with Dropbox. The problem turned out to be Arch Linux adopting dbus-broker instead of dbus-daemon. I reverted to using dbus-daemon and now Dropbox works perfectly. I'm posting this here even though it is solved for me in case some other Arch user is having a problem.
