diff --git a/mace/cli/run_train.py b/mace/cli/run_train.py
index e8319ac7..1c0898b7 100644
--- a/mace/cli/run_train.py
+++ b/mace/cli/run_train.py
@@ -335,8 +335,21 @@ def run(args: argparse.Namespace) -> None:
             )
             head_config_pt.collections = collections
             head_configs.append(head_config_pt)
+
+        ratio_pt_ft = size_collections_train / len(head_config_pt.collections.train)
+        if ratio_pt_ft < 0.1:
+            logging.warning(
+                f"Ratio of the number of configurations in the training set and the in the pt_train_file is {ratio_pt_ft}, "
+                f"increasing the number of configurations in the pt_train_file by a factor of {int(0.1 / ratio_pt_ft)}"
+            )
+            for head_config in head_configs:
+                if head_config.head_name == "pt_head":
+                    continue
+                head_config.collections.train += head_config.collections.train * int(
+                    0.1 / ratio_pt_ft
+                )
         logging.info(
-            f"Total number of configurations: train={len(collections.train)}, valid={len(collections.valid)}"
+            f"Total number of configurations in pretraining: train={len(head_config_pt.collections.train)}, valid={len(head_config_pt.collections.valid)}"
         )
 
     # Atomic number table