I am having the same problem and can not see my visual editor after updating to 4.2. I have tried everything, plugin deactivation, cleared cookies and cache, reinstalled wordpress manually and still no visual editor. I have read more comments about this that I can handle and so far nothing has worked. This is so frustrating. I have been trying to figure this out for 3 hours. ugh! I am using google chrome on a mac. Please help!!!