diff --git a/expo/MCTS.py b/expo/MCTS.py
index 5cd357989..228671e2c 100644
--- a/expo/MCTS.py
+++ b/expo/MCTS.py
@@ -40,6 +40,7 @@ def create_initial_state(task, start_task_id, data_config, low_is_better: bool,
         "start_task_id": start_task_id,
         "low_is_better": low_is_better,
     }
+    os.makedirs(initial_state["node_dir"], exist_ok=True)
     return initial_state