diff --git a/src/sempy_labs/_helper_functions.py b/src/sempy_labs/_helper_functions.py
index f8190f2c..04558727 100644
--- a/src/sempy_labs/_helper_functions.py
+++ b/src/sempy_labs/_helper_functions.py
@@ -1003,6 +1003,7 @@ def build_schema(schema_dict, type_mapping, use_arrow=True):
 
         if merge_schema:
             write_args["schema_mode"] = "merge"
+            write_args["engine"] = "rust"
 
         write_deltalake(**write_args)
     else: