I have just installed vagrant box with command:
vagrant init ubuntu/xenial64
and the booted it up with:
vagrant up --provider v
For some reason ubuntu/xenial64 doesn't come with a synced /vagrant folder.
I had to setup my own in the vagrant file:
config.vm.synced_folder ".", "/vagrant"
The first option is the source (Windows) the second is the target (Ubuntu)
Vagrant Synced Folders