Trying to upload a file, I get:
Upload Failure Aug 7 2017 12-26 PM.webm Exception: No configured storage engine can store this file. See "Configuring File Storage" in the documentation for information on configuring storage engines.
Of course, it happens after I waited for several minutes for the file to load :) If we don't allow uploading files (which we should?) we should at least have an early warning.