我在./data内添加了一个新文件夹boxes\ubuntu-xenial64\，并通过取消注释此行来编辑Vagrantfile：
config.vm.synced_folder "./data", "/vagrant_data"
获取如下错误：
PS C:\Users\sridh\.vagrant.d\boxes\ubuntu-VAGRANTSLASH-xenial64> vagrant up
C:/HashiCorp/Vagrant/embedded/mingw64/lib/ruby/2.3.0/rubygems/version.rb:207:in `initialize': Malformed version number string data (ArgumentError)
from C:/HashiCorp/Vagrant/embedded/mingw64/lib/ruby/2.3.0/rubygems/version.rb:199:in `new'
from C:/HashiCorp/Vagrant/embedded/mingw64/lib/ruby/2.3.0/rubygems/version.rb:199:in `new'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/box_collection.rb:289:in `block (2 levels) in find'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/box_collection.rb:285:in `map'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/box_collection.rb:285:in `block in find'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/box_collection.rb:448:in `block in with_collection_lock'
from C:/HashiCorp/Vagrant/embedded/mingw64/lib/ruby/2.3.0/monitor.rb:214:in `mon_synchronize'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/box_collection.rb:447:in `with_collection_lock'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/box_collection.rb:271:in `find'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/vagrantfile.rb:167:in `block in machine_config'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/vagrantfile.rb:200:in `machine_config'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/vagrantfile.rb:45:in `machine'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/environment.rb:733:in `machine'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/plugin/v2/command.rb:177:in `block in with_target_vms'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/plugin/v2/command.rb:201:in `block in with_target_vms'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/plugin/v2/command.rb:183:in `each'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/plugin/v2/command.rb:183:in `with_target_vms'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/plugins/commands/up/command.rb:87:in `execute'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/cli.rb:42:in `execute'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/lib/vagrant/environment.rb:308:in `cli'
from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.9.8/bin/vagrant:138:in `<main>'