Problems with Garage Band using MG with New MacBook

I have a new MacBook. I needed to reinstall Midi Guitar. I have downloaded MidiGuitar from the Apple Store. Everything looked good except when I try to record a midi track in GarageBand. I get no signal on the midi track. Is there a setting that I am missing?

Ok, so I guess you have both tracks (audio and MIDI Instrument) armed for recording? And do you see any action (lines moving as you play) in the MG2 plugin MIDI Velocity window/box?