启动 Homestead 时，报错

搭建开发环境时，启动homestead的时候，报以下错误，
$ cd ~/Homestead && vagrant up
Bringing machine 'homestead-7' up with 'virtualbox' provider...
==> homestead-7: Importing base box 'lc/homestead'...
==> homestead-7: Matching MAC address for NAT networking...
==> homestead-7: Checking if box 'lc/homestead' is up to date...
A VirtualBox machine with the name 'homestead-7' already exists.
Please use another name or delete the machine with the existing
name, and try again.

在网上查了一下解决方法看得糊里糊涂的，后来我直接手工启动virtualbox后，选中提示中所说的已存在的虚拟机，直接右键删除，就OK了。