I had Radarr pointed to the "Movie" folder, then I changed it to the "Media" folder thinking that that would somehow be "better".
Whoosh It was all gone the next time I looked, because it couldn't find entries for whatever it came across, I guess. I ended up having to re-design the whole environment from pretty much scratch. The good news was that since I had "imported" my library initially, I had references to most of the stuff I lost.
Rage-baited!