diff --git a/plugins/providers/virtualbox/synced_folder.rb b/plugins/providers/virtualbox/synced_folder.rb
index 49d403e44..2ce0f82c1 100644
--- a/plugins/providers/virtualbox/synced_folder.rb
+++ b/plugins/providers/virtualbox/synced_folder.rb
@@ -85,7 +85,7 @@ module VagrantPlugins
       end
 
       def os_friendly_id(id)
-        id.gsub(/[\/]/,'_').sub(/^_/, '')
+        id.gsub(/[\/\\]/,'_').sub(/^_/, '')
       end
 
       # share_folders sets up the shared folder definitions on the