I just had the same thing happen because I knocked the usb plug of the drive I’ve got plugged into my desktop and it ejected. I had Engine Prime open at the time and had just finished adding some music.
It’s a Samsung MZ-76E1T0B/EU 1 TB 860 EVO Sata III 64L V NAND Solid State Drive. I was planning on filling it and putting it inside the Prime so it’s got around 300gb on it now. The files are all displaying still in Engine Library/Music and I can still see one out of the 10 or so Crates I had built but inside Engine Prime and the Prime 4 it’s saying it’s corrupted.
This took me -weeks-… I am super bummed.