diff --git a/src/stream/src/from_proto/over_window.rs b/src/stream/src/from_proto/over_window.rs
index 3fa8929b4feb3..0ee5d6d8789ec 100644
--- a/src/stream/src/from_proto/over_window.rs
+++ b/src/stream/src/from_proto/over_window.rs
@@ -74,7 +74,9 @@ impl ExecutorBuilder for OverWindowExecutorBuilder {
             state_table,
             watermark_epoch: stream.get_watermark_epoch(),
             chunk_size: params.env.config().developer.chunk_size,
-            cache_policy: OverWindowCachePolicy::from_protobuf(node.get_cache_policy()?),
+            cache_policy: OverWindowCachePolicy::from_protobuf(
+                node.get_cache_policy().unwrap_or_default(),
+            ),
         })
         .boxed())
     }