USB malfunction mid set.

I was djing on my XDJ RX2. I started to loop a beat when everything flashed and the unit malfunctioned. The xdj put both tracks into an automatic emergency loop and my USB stopped working. It's been working fine for months. It hasn't been damaged. It worked for a good hour before the malfunction. Now the XDJ won't read it at all and is giving me an E-8307 error code every time I reinsert it. Any ideas what's wrong?