Ok after a LOT of googling, disabling the System Integrity of my mac, and some more googling. Like, literally hours worth, I found a post regarding NFS. I use vagrant for work and it looks like the pioneer software can't handle having an NFS daemon running at the same.
Can you please make this a) Slightly less terrible for the end user who has to wander around broken links and shitty unsolved threads with no response (talk about demoralising), and b) Make the software a bit more robust? I use vagrant everyday, and I have to move the /etc/exports file and restart just to get rekordbox to run as it should. This is not good enough for industry standard software on devices costing thousands of dollars. Why is it even creating a USB network? Use the protocol, it's fast enough for Serato and Traktor.