diff --git a/lib/vagrant/action/builtin/box_add.rb b/lib/vagrant/action/builtin/box_add.rb
index ec8c04761..80d5b10ce 100644
--- a/lib/vagrant/action/builtin/box_add.rb
+++ b/lib/vagrant/action/builtin/box_add.rb
@@ -485,7 +485,8 @@ module Vagrant
           mutex_path = d.destination + MUTEX_SUFFIX
           if File.file?(mutex_path)
             raise Errors::DownloadAlreadyInProgress,
-              dest_path: d.destination
+              dest_path: d.destination,
+              lock_file_path: mutex_path
           end
 
           begin
diff --git a/templates/locales/en.yml b/templates/locales/en.yml
index a20c6ce79..095f83384 100644
--- a/templates/locales/en.yml
+++ b/templates/locales/en.yml
@@ -901,6 +901,7 @@ en:
         a file to the same location.
 
         Download path: %{dest_path}
+        Lock file path: %{lock_file_path}
       downloader_error: |-
         An error occurred while downloading the remote file. The error
         message, if any, is reproduced below. Please fix this error and try