So last weekend I was using the XDJ-RX at a private party. Everything went fine until I was browsing through a playlist. Suddendly the whole thing froze and I had to turn it off and on in order to make it work again. It happened a couple of times during the evening which was really upsetting. Luckily it was just a private party.
So the next day I was trying to figure out what was wrong. I found out that it only happened while browsing through a specific playlist and I could finally locate the track which caused the problem. I thought that maybe the file is corrupt or the USB-Stick is having a problem, so I connected the XDJ directly to my RekordBox via the LAN cable. Here it worked, so I tried again using the USB-Stick and it froze again.
Then I used the sync manager, deleted that playlist and rewrote it back on the stick. Now it worked without crashing.
So I can only assume that during the first syncing, rekordbox failed to write that file properly onto the stick. The XDJ really should recognise broken files and prevent freezing. I have the latest Firmware installed (1.30)