Yes indeed, I have also endured the same annoying, repetitive problem, and have tried removing my firewalls to resolve it, but unfortunately, that did not work at all. The "connecting to update server" crawl just keeps on sliding along, and if you 'hide' it, it doesn't do any good. No update. I have been a big Firefox fan for many years now, and am solidly surprised that such a sophomoric upgrade error is extant right at the beginning of a major version update like 4.0. I really hope that you guys will resolve this ASAP... '''U P D A T E''' Well, I received a useful reply, from a support person, and although I did not follow the instructions exactly, it seems to have completely solved the problem. You can go to [https://support.mozilla.com/en-US/questions/830160#answer-193798 this link], where I re-posted this problem, to read all of the gory details... :)