I'm trying to record from line-in but my OSX 10.9.1 does not seem to have a line-in device!? Both system preferences and audio midi only show build in microphone as input. Is this a known issue or what am I missing?
I know this is an old question, but I've had the same problem. If you have a Macbook Retina Pro, it doesn't have an audio line in built in as opposed to the next model down (without the Retina screen). I have no idea why Apple decided to remove the port from the Retina model, since it can't cost them that much.