diff --git a/Library/Homebrew/sandbox.rb b/Library/Homebrew/sandbox.rb
index 435db739ee..9054372bf2 100644
--- a/Library/Homebrew/sandbox.rb
+++ b/Library/Homebrew/sandbox.rb
@@ -118,6 +118,7 @@ class Sandbox
       if @failed && ARGV.verbose?
         ohai "Sandbox log"
         puts logs
+        $stdout.flush # without it, brew test-bot would fail to catch the log
       end
     end
   end