diff --git a/.travis/build_package.sh b/.travis/build_package.sh
index 4bbd9846925..7d924a55f80 100755
--- a/.travis/build_package.sh
+++ b/.travis/build_package.sh
@@ -87,6 +87,7 @@ do
 	  then
 	        echo "The matrix and the actual package list differ : ."
 					echo ${DIFFERENCE[*]}
+            echo "You should run generate_travis.sh."
 	        exit 1
 	  fi
 	  echo "Matrix is up to date."