The BEHRINGER UCG102 can be setup on a Mac based computer using the following steps:1. Plug your UCG102 in to your Mac and the light on the unit should come on. This light will be blue on older models of this unit and orange on newer models of this unit.2. The UCG102 should be seen by your Mac as a USB AUDIO CODEC. Please check your Mac's sound preferences when the unit is connected to see if it does show up as a USB AUDIO CODEC. If it does, then please select it for the INPUT.4. Plug your guitar into the GUITAR INPUT of the UCG102, play it for a bit, and see if you can see signal showing up on the INPUT LEVEL meter on the sound preferences screen. You will not hear anything at this point. You should only see signal on the INPUT LEVEL meter on the sound preferences screen. If you do see the signal, then the unit is working properly.5. You will then need to open up the software that you would like to use with your UCG102 and choose the USB AUDIO CODEC as the audio input for that software. If you would like to hear the signal coming back out of the headphone output on the UCG102, then you will need to set the output of the software to be the USB AUDIO CODEC as well. All sound will then be processed by the software.