Thanks for your help. You give me a clue to deal with this problem! I immediately found this http://support.mozilla.com/zh-TW/questions/800955#answer-155360

Thanks for your help. You give me a clue to deal with this problem! I immediately found this http://support.mozilla.com/zh-TW/questions/800955#answer-155360 http://support.mozilla.com/zh-TW/questions/800955#answer-155... And carefully checked all of my extensions. I found a Z extension hide itself in FF extensions list. Finally I deleted it. I think this is a good way if FF can give users some clue to deal with crash problem. It might be a great help. Thank you.