Suddenly no song audio but only in performance mode. RBv5

Hi, I've got a had a DDJ400 running Rekordbox 5 for a couple of years now, never an issue. Today I was upstairs loading some new songs, correcting them in export mode, all fine, when I pressed to activate the 30 day trial so I had access to performance mode without going down to my deck setup. All playing fine. Closed rekordbox, gone downstairs, plugged my ddj in, and boom, no audio. However, sample audio is fine, as are headphones, and also in export mode, all fine, but performance mode, zero track audio, and the only thing out of the ordinary is activating that trial. I've reinstalled, system restored. I'm out of ideas. Any help appreciated.