If you ran into this issue then it most likely means that you uninstalled VirtualBox or deleted the VM. Please see How can I restore a site from a Local site folder?
Please see How can I restore a site from a Local site folder? as well.
Sorry for the trouble!
Just a heads up, in 2.2.1 and newer there will be a button to restore sites with one-click if you delete VirtualBox or Local’s VM in VirtualBox.