Hi guys I'm trying to record my guitar through my mac but im having some trouble. Currently I have my guitar plugged into the line in on the audio interface (tascam us-144) and the line out into the macbook's line in port and the headphone port on my mac with the monitor. In garageband how do I set it up so that I can record guitar?
So your imput is throught the line in and not via usb.
Settings, audio, make sure your imput is selected.

Open gb, create basic track, find the monitor and imput selector, set to monitor with no feed back protection and a mono imput for guitar. Hit r to start recording then space to stop. Should be able to hea yourself now.
Let me know if there are problems