diff --git a/RELEASES.md b/RELEASES.md
index b569e5e165b3..f827ee61d3be 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -92,6 +92,7 @@ This will be the final release with support for the dYdX v3 (legacy) API. Future
 - Fixed Polymarket duplicate trade_id for multi-order fills (#3450), thanks for reporting @santivazq
 - Fixed Polymarket `load_all_async` ignoring time-based filters (#3475), thanks @Coyote-Den
 - Fixed `MarketIfTouchedOrder` fill price during bar processing to use trigger price instead of bar extremes, thanks @HaakonFlaaronning
+- Fixed Avoid OOM error in backtest by setting optimize_file_loading default value to False.
 
 ### Internal Improvements
 - Added support for setting cache database adapter in cache and `LiveNode` (#3401), thanks @filipmacek
diff --git a/nautilus_trader/persistence/catalog/parquet.py b/nautilus_trader/persistence/catalog/parquet.py
index 2c3710155399..55d8f2d4feaa 100644
--- a/nautilus_trader/persistence/catalog/parquet.py
+++ b/nautilus_trader/persistence/catalog/parquet.py
@@ -1651,7 +1651,7 @@ def backend_session(
         where: str | None = None,
         session: DataBackendSession | None = None,
         files: list[str] | None = None,
-        optimize_file_loading: bool = True,
+        optimize_file_loading: bool = False,
         **kwargs: Any,
     ) -> DataBackendSession:
         """