Once I upgraded to 3.9, I lost the visual editor and can't add media. I also lost the easy-to-insert theme shortcodes.
I've tried deactivating all plugins and emptying the browser cache, doesn't make any difference. I'm trying all these kind suggestions on both Safari and Internet Explorer.
Now I tried inserting SCRIPT_DEBUG into the config.php, still no difference on either browser.
I´m a total beginner, if anyone has a moment to help, it would be much appreciated. Thanks!