It's a long story but it's been driving me and everyone i ask insane. Please help! It all started when I recently bought a Pioneer DJM-900srt and switch from Traktor to Serato Dj. Now, I have been using my current Korg Nanocontrol for about 2 years problem free using manly Ableton Live 8 and Traktor Pro 2. Never needing to download any drivers and/or control editors. Fast forward to recently. Unknown to me at the time Serato Dj had some known issues with Midi mapping (that i should of researched more) but I went ahead and downloaded the latest Korn Nancontrol driver and control editor. Thinking 1) It might solve my Serato Dj problem and 2) what could it hurt? The second turned to be a nightmare. So before I downloaded the driver and control editor I could plug in and unplug any of my midi usb devices, audio interfaces and Dj mixer in no specific order and at anytime and every thing would work and midi map as it was meant to. However, after downloading the driver all hell broke loose. While the driver was on my laptop none of my listed midi devices would connect properly and half the time the program would fail or just not open. I know you're not Allen & Heath but I also tried to download the latest driver from their website for my non working Xone 1D; Ableton, Serato Dj and Audio/Midi setup in utilities just will not open so i cant even tell if the midi devices are functioning properly. So I went on and deleted the Korg driver, editor and the Xone 1D driver. After deleting the drivers and Korg control editor things now somewhat work but far from how they should. In order for things to function somewhat properly I must turn on the devices in this exact order. Turn on the computer and let it fully boot up. Plug in via USB to my laptop and turn on the Djm-900srt. Plug in my USB 7 port extender (with power supply) plug in my Korg Nano and my Maschine Mikro into the extender and turn it on. Boot up Ableton to quickly check if the devices mounted properly. Open up either Traktor or Serato and rock the house. The Allen & Heath Xone 1D has been dead in the water since the initial Korg Driver instal. I can get screen shots of anything if it will help after work today. Around 5pm CST Detailed specs: Computer- Model Name: MacBook Pro Model Identifier: MacBookPro6,1 Processor Name: Intel Core i7 Processor Speed: 2.66 GHz Number Of Processors: 1 Total Number Of Cores: 2 L2 Cache (per core): 256 KB L3 Cache: 4 MB Memory: 4 GB Dj Gear- Mixer - Djm-900srt Midi Devices - Korg Nanokontrol 1st gen, Maschine Mikro 1st gen, Allen & Heath Xone 1D P.S. Any new USB device will not function or be recognized.