I have a 13' Macbook Pro currently running Yosemite 10.10.5, but my Audiobox iTwo isn't connecting to it. The iTwo's lights turn on when I plug it in, but it doesn't show up as an option in Garageband (I know, I'm amateur), or in the Sound section of System Preferences. The only option for both is the built in microphone. One weird thing is that in Garageband, it asks me what input I want to record from (with the options Input 1, Input 2, and Both; however, every option just hears audio from the built in input. I don't seem to remember it asking me this before I got my Audiobox, and I have no idea what that could be referring to aside from the two inputs on the iTwo.
I have tried 'Hotplugging' it, as the compatibility statement for Yosemite said to, to no avail. I am also currently downloading OSX El Capitan, though I would rather not update my OS on the hope that it will make my Audiobox work, and end up making it worse.