UR44 + Macbook + Garage Band = problems

Just have to ask and sorry if this seems like a stupid question but, did you install the latest TOOLS_for__V213_MAC before plugging in your devices?

You should see on Launchpad a) Yamaha Steinberg Control Panel b) dspMixFx for your version of interface.
You should also see your interface listed in Audio MIDI Setup under Utilities.