For some reason I got a blog crashed today and I wasn’t able to upload new media files to the library either to an article.
I was searchin a bit and were disabling some plugins, but it didn’t matter. So well, I just found out that I had occurrenced this problem, when I integrated a new JQuery Version on my own.
If you’ve got this problem too, just look if there are any plugins which are embedding the jquery library and gettin in conflict with the integrated core-jquery of wordpress in 3.3. or if you integrated it on your own – put it out and see, if it’ll work! 🙂