diff --git a/arkane/statmech.py b/arkane/statmech.py
index ec76426c00f..6260e604b96 100644
--- a/arkane/statmech.py
+++ b/arkane/statmech.py
@@ -254,7 +254,8 @@ def load(self, pdep=False):
         try:
             linear = local_context['linear']
         except KeyError:
-            externalSymmetry = None
+            logging.error('You did not set whether the molecule is linear with the required `linear` parameter')
+            raise
 
         try:
             externalSymmetry = local_context['externalSymmetry']