The current MIDI control center does not work with Mavericks either. I opened a ticket with Arturia support and they practically said that it is Apple's fault for updating their operating system. I kid you not, that is what I was told. Luckily, I do have a MacBook with Yosemite installed, the MIDI Control Center works there - although it doesn't recognize the Keylab right out-of-the-box and you will have to delete the MIDI Device and Keylab device in Audio/MIDI, run MCC, plug the Keylab in and that should get you going. Hopefully, you have another Mac with Yosemite installed too. Hope this helps.
