diff --git a/src/stream/src/from_proto/over_window.rs b/src/stream/src/from_proto/over_window.rs
index f3833464c0fc..7d139ca3f74d 100644
--- a/src/stream/src/from_proto/over_window.rs
+++ b/src/stream/src/from_proto/over_window.rs
@@ -75,7 +75,9 @@ impl ExecutorBuilder for OverWindowExecutorBuilder {
             watermark_epoch: stream.get_watermark_epoch(),
             metrics: params.executor_stats,
             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())
     }