Hello James,
MacOS Sierra is not supported for the moment. There are known issues on the newest Apple computers. We are currently working on it, and it should be supported in the next version.
Updates about the MacOS version of Pix4D software are announced in the official forum post: https://community.pix4d.com/t/5672 If you would like to be notified of updates, please login and click “Follow” on the top right corner of the post.
Thank you for your understanding.
Best,