Clean out the fonts folder. Maybe there is a file that Indesign doesn’t like.
Try one of the other Fonts folders. There are several, I have the best experiences with this: /Library/Application Support/Adobe/Fonts/. But there is one in the user library, several in the Applications folder (one for each app).
Make sure that you have write permissions in the folder you exporting into.
Uninstalled & reinstalled CC apps. No joy. Oh well.
Right now I’m putting fonts in a users/maxphillips/Library/Fonts alias, and then using the latest FontNuke to clear the caches. So I can work again, but it would sure be nice if I didn’t have to keep restarting.
What helped a little bit was restarting InDesign with Shift+Ctrl+Alt+Cmd held down (yes, all four of them), until it asks you if you want to delete prefs. To be on the safe side, restart the Mac twice: first with Shift (safe mode, clears caches), then without Shift.