我最近在我的电脑上安装了Docker Toolbox（OS X），虽然我已经在另一台笔记本电脑上成功地使用它，但在这台电脑上似乎无法正常工作。按照Docker文档的说明，使用Docker Toolbox进行安装并通过docker命令行工具启动后，出现了主机未运行错误的情况。
Machine default already exists in VirtualBox.
Starting machine default... exit status 1 Started machines may have new IP addresses. You may need to re-run the docker-machine env command. Setting environment variables for machine default...
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host is not running docker is configured to use the default machine with IP For help getting started, check out the docs at https://docs.docker.com
default is not running. Please start this with docker-machine start default
尝试使用docker-machine start default启动主机也无法成功启动：
bash-3.2$ docker-machine ls
NAME ACTIVE DRIVER STATE URL SWARM
default virtualbox Stopped
bash-3.2$ docker-machine start default
exit status 1
Started machines may have new IP addresses. You may need to re-run the `docker-machine env` command.
bash-3.2$ docker-machine ls
NAME ACTIVE DRIVER STATE URL SWARM
default virtualbox Stopped