diff --git a/app/__init__.py b/app/__init__.py
index 6fb6cf05..5217736f 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -550,3 +550,22 @@ def scodoc_flash_status_messages():
             f"Mode test: mails redirigés vers {email_test_mode_address}",
             category="warning",
         )
+
+
+def critical_error(msg):
+    """Handle a critical error: flush all caches, display message to the user"""
+    import app.scodoc.sco_utils as scu
+
+    log(f"\n*** CRITICAL ERROR: {msg}")
+    send_scodoc_alarm(f"CRITICAL ERROR: {msg}", msg)
+    clear_scodoc_cache()
+    raise ScoValueError(
+        f"""
+    Une erreur est survenue. 
+    
+    Si le problème persiste, merci de contacter le support ScoDoc via 
+    {scu.SCO_DISCORD_ASSISTANCE}
+    
+    {msg}
+    """
+    )
diff --git a/app/comp/moy_mod.py b/app/comp/moy_mod.py
index dfced34c..1fccbda1 100644
--- a/app/comp/moy_mod.py
+++ b/app/comp/moy_mod.py
@@ -39,6 +39,7 @@ from dataclasses import dataclass
 import numpy as np
 import pandas as pd
 
+import app
 from app import db
 from app.models import Evaluation, EvaluationUEPoids, ModuleImpl
 from app.scodoc import sco_cache
@@ -484,7 +485,8 @@ class ModuleImplResultsClassic(ModuleImplResults):
         if nb_etuds == 0:
             return pd.Series()
         evals_coefs = self.get_evaluations_coefs(modimpl).reshape(-1)
-        assert evals_coefs.shape == (nb_evals,)
+        if evals_coefs.shape != (nb_evals,):
+            app.critical_error("compute_module_moy: vals_coefs.shape != nb_evals")
         evals_notes_20 = self.get_eval_notes_sur_20(modimpl)
         # Les coefs des évals pour chaque étudiant: là où il a des notes
         #  non neutralisées