diff --git a/plugins/providers/virtualbox/driver/version_4_3.rb b/plugins/providers/virtualbox/driver/version_4_3.rb
index 2d257a8c1..81f2252b6 100644
--- a/plugins/providers/virtualbox/driver/version_4_3.rb
+++ b/plugins/providers/virtualbox/driver/version_4_3.rb
@@ -499,7 +499,7 @@ module VagrantPlugins
             args = ["--name",
               folder[:name],
               "--hostpath",
-              folder[:hostpath]]
+              Vagrant::Util::Platform.windows? ? ("//?/" + File.expand_path(folder[:hostpath])).gsub("/","\\") : folder[:hostpath]]
             args << "--transient" if folder.key?(:transient) && folder[:transient]
 
             # Enable symlinks on the shared folder