DockerFAQ

動作しない

$ docker build -t hoge .
Cannot connect to the Docker daemon. Is the docker daemon running on this host?

$ eval $(docker-machine env default)
Error checking TLS connection: default is not running. Please start it in order to use the connection settings

解決法

$ docker-machine start default

dockerコマンドが実行出来ない

$ docker ...
Cannot connect to the Docker daemon. Is the docker daemon running on this host?

解決法

$ eval $(docker-machine env default)

参考：Mac でのDocker docker-machineのトラブルまとめ - Qiita