My M-Audio Fast Track stops working when switching instruments/tasks in Garageband.

I bought an M-Audio Fast Track along with a few imacs for my students to use in my classroom. I have it installed and it works sometimes. I seem to have to have a fresh restart of osx and garageband, then it picks up the guitar and its usable with all the effects and cool stuff in garageband. If I switch something, like add another instrument guitar track, or switch to another task like browse for a bit then come back it stops working. I cannot get it to work again without restarting osx. It does not pickup the fast track if I restart garage band or replug in the usb.

I bought this through apple, so I figured it was supported and would work great for my stuents. I have found support has changed for this device.

Any tips before I look into returning it?

Sean