Updated to 4.5. Media and Categories don't work properly.

I just updated to 4.5, and am having issues with media and categories now. When I go to add a featured image, it brings up the media screen full page, with no way to get back to the post I was editing. The media button above the content block doesn’t even do anything. Nothing pops up, doesn’t go to any pages to add media.

Also when trying to select categories, clicking on the Most Used link does nothing. And when I try to type them in manually, saving the page doesn’t save them because they were not added.

So I suppose I need to see if there’s a plugin thats causing this, correct? This is on a Multi-blog site, so a lot of the plugins are network activated. Is there any way to turn them off for this one specific blog, so that I don’t turn them off for the other sites that are live?