I just upgraded from 3.4 to 3.5. I've tried 3.5, 3.51, and 3.52. All of my media seems to show up everywhere fine except when I'm creating / editing a post or page and click on "add featured image". When I do that, none of the thumbnails load on the popup.
I have tried deleting all of the plugins and using the default theme with no luck. Anyone have any ideas what the problem could be?