USB's not recognised on the XDJ-RR (Tried various fixes)

I just can't get a looooad of my tracks to load in the XDJ-RR. I get the E-8305 error. I've tried exporting the files out of Audition and Audacity with different output settings, but I still have the same error. I even tried WavFix, and all the files showed up green, like there were no issues, but yeah, still won't play.

I've tried various USB's, reformatted them etc, still nothing.

Any help? I'm pretty close to sending this unit back. 

Cheers.