diff --git a/tool/.travis.sh b/tool/.travis.sh
index f44abf0d..74960061 100644
--- a/tool/.travis.sh
+++ b/tool/.travis.sh
@@ -1,4 +1,4 @@
 cd angel_serialize_generator
 pub get
-pub run build_runner build
+pub run build_runner build --delete-conflicting-outputs
 pub run test
\ No newline at end of file