Loop Browser not working in Logic X (10.5.1)

The CAF files are there in my Library/Audio/Apple Loops/Apple folder. I can drag and drop them from Finder to the Logic playhead (they work fine), but they refuse to show up in the Loop Browser despite re-indexing, re-installing, etc. I can't even drag and drop files into the browser. I get an infinite "Indexing Apple Loops Library" pin-wheel.

Any thoughts? The GarageBand Loop Browser works perfectly fine, on the same Mac.

Of course I can just take the extra step and preview and browse them with the "All Files" Browser, but it seems bizarre and irritating that I can't just use the Loop Browser.