Thanks for the reply. I hadn't quit Kitematic by the time I started Quickstart Terminal, but Kitematic had completed the creation of its VM: docker-machine ls

Thanks for the reply. I hadn't quit Kitematic by the time I started Quickstart Terminal, but Kitematic had completed the creation of its VM: docker-machine ls showed default as running, and the docker cli button at the bottom of the window opened a usable docker session in that machine. It looks like Quickstart Terminal looks for the default VM using VBoxManage, rather than docker-machine, and hardcodes its location as /usr/local/bin. Mine's in /usr/bin, so the script failed to detect the existing machine. I don't have time to report this now, but I'll look at filing an issue this evening.