I'm having the same problem. There is at least one other post with another 8 people having the same problem. No one has come up with a solution yet. I've tried reinstalling..doesn't work. Upgraded Java for Mac...doesn't work. I hope someone has an answer soon!!

I've just sorted this problem!!! I restarted with add-ons disabled and started enabling them one by one and found there was an issue with one of them. I've now removed the add on and everything is starting fine again. Hope this works for you too!!

I've just sorted this problem!!! I restarted with add-ons disabled and started enabling them one by one and found there was an issue with one of them. I've now removed the add on and everything is starting fine again. Hope this works for you too!!

I ended up purging the entire system of Firefox including the cache because I couldn't update two of the plug ins. I installed Firefox again but still don't have a bookmark bar. Importing bookmarks from Safari is no longer a couple of clicks. First I had to export the file from Safari, and it installed on a dropdown menu. That's too much like Internet Explorer. At least with IE you can choose which version to use. Everything I liked on Firefox 9 is gone in Firefox 10...or at least I can't find it!  :D