I'll allow myself to link to the thread I originally opened in the wrong subforum (sorry for that): http://forums.mozillazine.org/viewtopic ... &t=3029149
While stable release works like a charm with the given profile, Earlybird started acting up today. First it did neither download nor send mail, and when I closed it and tried to open it again, the error mentioned in the other thread occurs. Reinstalling didn't change anything.