Greetings! I just recently bought a Prime 4 (previous unit was the MCX8000). I’m currently using it in computer mode until I get used to the standalone setting. I haven’t seen any topics on this yet but does anyone know if it is possible to switch from my laptop program (Serato) to my usb drive? On my mcx8000 I could do it easily by switching to engine on the channel I wanted to use it on. Any help is greatly appreciated as I’m still learning the ropes for it.
Thank you!!! 
Unfortunately this isn’t possible on the Prime series.
I too came from an MCX8000 and hit this limitation a few years ago. I don’t think it is possible with the way the Prime 4 is an actual operating system (Linux style) with an app that plays the music. You have to exit this ‘player’ mode to get to the controller mode. It’s not seamless.
Prime 4 (and other Prime units) are really dropping the laptop with their forward thinking and while they are’t quite there yet (for some things like video etc), they are getting closer with each release.
The MCX8000 didn’t run an actual OS so it was easier to do this switching kinda thing. It’s a shame but unfortunately it’s the nature of the beast with the Primes.
I had a feeling that would be the case. It shouldn’t be much of a problem once I get used to using serato on the standalone setting. But still annoying if I want to use the usb I have to close serato and then switch to standalone mode.
Well, thanks again! 