How to fix some Vagrant issues

Here are some issues you will face when playing around with Vagrant and how to fix them:

1. Cannot install plugin

Remove ~/.vagrant.d directory before re-installing vagrant.

2. 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.

Remove .vagrant file.

3. Cannot run a vm with Vitualbox:

Enable VT-x feature in your machine's BIOS.