mitchellh/vagrant — pull request #846 by skarab (2012-03-29 14:36:01+00:00)
Title: Detect when the VirtualBox installation is incomplete and error

After a kernel upgrade without rebuilding the VirtualBox kernel modules, Vagrant gave the following error:

Vagrant has detected that you have a version of VirtualBox installed
that is not supported. Please install one of the supported versions
listed below to use Vagrant:

4.0, 4.1

I saw [GH-677] and noticed that VBoxManage was complaining with the following error:

$ VBoxManage --version
WARNING: The character device /dev/vboxdrv does not exist.
Please install the virtualbox-ose-dkms package and the appropriate
headers, most likely linux-headers-generic.

You will not be able to start VMs until this problem is fixed.
4.1.2_Ubuntur38459

Because it didn't fit the error output matched in ce2ea4ea9339e0292b9f85574e59fd8868e1669e, I've added an additional error condition check which warns of an incomplete VirtualBox installation.