Fix for visual editor empty, text editor has full html content

the visual editor is empty, but the text editor has full html content on only one site. I cloned the site to another server and the problem existed on both servers. I checked out several of the support issues citing the same problem and tried
1. Deactivating all plugins
2. Changing to default theme
3. Clearing browser history/cache
None of these worked. I then used FTP to replace the wp-includes/js/tinymce directory on one server install and it worked again.
I tried only replacing the tinymce directory on the other server and it didn’t work until I also deactivated all plugins and changed the theme. There may be something in one of those that hung-up the tinymce replacement.
It’s a long way around but it worked for me.