Hi Nick,
I don’t know from which year your computer is, but the beta Mac version seems to support only models that are from 2014 or more recent. Perhaps this could explain the issue. I saw this information here: https://community.pix4d.com/t/5087
Perhaps you could try to run bootcamp on your mac to create a windows session for Pix4d on windows, it may work better.
Regards,
Mathieu