diff --git a/.travis.yml b/.travis.yml
index ff6c46301..ff5f36275 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -48,3 +48,5 @@ notifications:
   irc:
     channels:
       - "irc.freenode.org#etherpad-lite-dev"
+
+# WARNING!  Travis has a cache, you have to clear it if you are having files exist which shouldn't.