Had many problems with Faderport and Cubase 6 but got it to work. Not using Cubase 8 Pro with Mavericks. Faderport not working. Got and Email from Presonus today:
We don’t support the FaderPort for Cubase 8. Only up to 6. Steinberg changed some of the internal programming and it broke our ability to function.
Of course Presonus won’t work with Steinberg to get it to work. Faderport has been lame from the stat. I only bought it to do Stereo Bus fades.