MBP not showing up as an Output/Zone

[Martin_Webster]

Make sure you have enabled the audio device.

And if you need to understand the difference between system and built-in output read this:

Difference between Built-in output and system output?[Answered]

To expand on the answer above a little bit: System Output is going to make Roon’s output function like any other application – audio is sent to the OSX mixer, where it’s mixed with other sources (Youtube, system sounds, etc). In many cases, the audio will be resampled during this process, so this mode is more about convenience than critical listening. For example, if you switch your default output from the Macbook’s speakers to a bluetooth device, Roon’s output will go with it, because it’s si…