Yosemite TSP 2 Experiences please post here.

Not sure if it’s related to Yosemite, but I had this issue a while back with Mavericks. Very frustrating.

Untick the option Import Music Folders at Startup. This worked, although I’m not sure why:

http://www.native-instruments.com/en/support/knowledge-base/show/2471/traktor-does-not-recognize-my-traktor-kontrol-x1-mac/

Hope that helps.