$ vagrant up
The provider 'virtualbox' that was requested to back the machine 'default' is reporting that it isn't usable on this system. The reason is shown below: Vagrant has detected that you have a version of VirtualBox installed that is not supported by this version of Vagrant. Please install one of the supported versions listed below to use Vagrant: 4.0, 4.1, 4.2, 4.3, 5.0, 5.1 A Vagrant update may also be available that adds support for the version you specified. Please check www.vagrantup.com/downloads.html to download the latest version.