Ok, Im using a macbook, garageband and a Tascam US-112l interface. It was working fine then all of a sudden there was no signal and there was no sound from my guitar! I created a real instrument track, had the input preference to the tascam (which the mac had found) and the built in output. The big problem is that the Recording Level Adjuster has greyed out at zero so i cannot increase it.

Does anyone know how to get rid of this??
Killing you for a smile
that same thing happened to me yesterday. just make a new track and delete the muted one. im not sure why that happens, but if you already have something recorded and want to keep it, just copy it, create a new track and then paste it in.
Glad im not the only one aha. I tried that but it hasnt worked. whenever I select the 122 it always greys out.

Cheers dude
Killing you for a smile
have you tried restarting your computer? sometimes they start acting up and just need a reboot.