Rekordbox export error (won't export certain files onto USBs)

Hi,

playing a gig tomorrow and was exporting my playlists to have an export log over 150 files long of files that couldn't transfer over. I've had export issues in the past with maybe 1 or 2 tunes, however this is the first time where it seems like the entirety of my most recent library update and more, simply won't sync onto a USB. I've tried a fat32 and a HFS+ formatted USB, but the same files won't export onto both USBs. I had a large program crash a couple months back that lead to hundreds of my cue points being corrupted so I basically reset the entire library but I am truly stuck as to why these files aren't exporting - it's a variety of Wavs, mp3s & flacs, different characters and title lengths etc. but still. Please help!