Hi. I have been using Prime 4 since it got out, and I always update to the latest Engine on Windows and firmware. I use a external drive (exfat), which is organized in folders for each year. All the music is on the external drive, and the crates have been showing up for each year. Its a bit frustrating because it seems that I had to export the crates each time when I add music on windows, even if everything is on the external drive. What happened last night was that all crates diasappeared, but all the music was still in the engine library. I unfortunately clicked yes when I closed the software so it made a backup, and this fantastic software only kept one backup so I could not retrieve it. When I got to the club all the music was there, but no yearly crates. I could see the history folders, so that was a bit helpful. Is this a bug or did I do something wrong?
Try plugging external drive into pc and running a chkdisk on it. Click yes to repair and try that in prime 4. It can hapoen if you unplug drive without ejecting first (Learnt hard way earlier this year)