Hello, I have been using traktor pro 1.2.7 for many years now, with audio 8 dj, 4 decks out of the card to the mixer, and osx 10.6.8. And my root directory is always on external disk with firewire. My interface was bought around 2007 but works 100%, and the drivers and firmware are the latest, firmware version 24, and drivers on 2.8 i think. I also use 2 X1 controllers, these are working fine. I never had any issues at all, rock solid performance. At my last gig, I decided to switch to my new laptop, which is on osx 10.11.4, exactly same setup just newer laptop with el capitan. Then BOOM, I had 4 audio dropouts in 4 hours. The dropout happens on all channels at the same time (master in other words), which I am guessing is a streaming problem. The waveforms on traktor are flowing properly, while the signal gets silent instantly, then there is distortion (like if you unplug an audio cable or when an audio cable is broken) almost white noise, and then the sound comes gradually back, all this lasting about 2-4 seconds. I have checked online, and I cannot figure out what's the problem, it happens totally at random times, so there is no specific reason why this happens. Many people said is the latest update on el capitan with USB devices? Any help would be greatly appreciated. Thanks!