博客轉自：http://doodlebobbers.com/vagrant-error-your-vm-has-become-inaccessible/
If you’ve deleted a virtual machine file still referenced by one of your projects, you’ll run into the following error when you try and instantiate the VM via vagrant up.
Your VM has become “inaccessible.” Unfortunately, this is a critical error with VirtualBox that Vagrant can not cleanly recover from. Please open VirtualBox and clear out your inaccessible virtual machines or find a way to fix them.
Vagrant creates a hidden folder within your project directory named .vagrant with files that refer to specific VM IDs.
Simply delete the .vagrant folder within your project and rerun vagrant up.
For giggles, here’s a Github issue page regarding this with a few more details.
在網上找了好久，終於找到了一篇可以解決的辦法。
其實就是刪除安裝目錄中的.vagrant 文件夾，然后在到命令行窗口下執行vagrant up
