diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index 5e0abe78b7..bd709195c2 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -672,7 +672,7 @@ module Homebrew
             If this is a surprise to you, then you should stash these modifications.
             Stashing returns Homebrew to a pristine state but can be undone
             should you later need to do so for some reason.
-              cd #{path} && git stash && git clean -d -f
+              cd #{path} && git stash -u && git clean -d -f
           EOS
 
           modified = status.split("\n")