Garageband stops picking up USB guitar

Hi there,

For a few months I've been using the USB to stereo jack cable that came with the Rocksmith xbox game I bought (and never played) to record my electric guitar in Garageband.

Everything was going fine, but in the last few weeks I have had an issue where the connection dies if I stop playing for more than about 5 seconds. For example, I fire up Garageband, plug in the USB cable, Garageband does its "initializing core audio" thing, I turn on monitoring and I'm good to go, everything is working smoothly.

Then I stop playing for a moment and the strings are muted. There is no sound input to my machine, and when I pick up the guitar again Garageband no longer recognizes the instrument is connected. The only surefire way to get it to recognize the guitar again is to unplug the USB cable, GB will "initialize core audio" as it switches back to the internal mic as the default audio input, and then I plug the USB cable back in.

I say the only surefire way because sometimes (seems to be totally at random), I am able to get it to pick up the guitar again simply by toggling the monitoring off and then back on.

This began a few weeks ago (may have updated yosemite or garageband in that timeframe but cannot remember - anywhere I can check this?), before that I could leave the guitar plugged in with the monitor on, walk away for an hour, come back pick it up and start playing again.

Running Garageband 10.0.3

Any help is appreciated, thanks!