diff --git a/app/scodoc/sco_edit_ue.py b/app/scodoc/sco_edit_ue.py
index af045bf0..7675e45e 100644
--- a/app/scodoc/sco_edit_ue.py
+++ b/app/scodoc/sco_edit_ue.py
@@ -250,7 +250,7 @@ def ue_edit(ue_id=None, create=False, formation_id=None, default_semestre_idx=No
         title = f"Modification de l'UE {ue.acronyme} {ue.titre}"
         initvalues = ue_dict
         submitlabel = "Modifier les valeurs"
-        can_change_semestre_id = ue.modules.count() == 0
+        can_change_semestre_id = (ue.modules.count() == 0) or (ue.semestre_idx is None)
     else:
         ue = None
         title = "Création d'une UE"
@@ -410,7 +410,7 @@ def ue_edit(ue_id=None, create=False, formation_id=None, default_semestre_idx=No
         submitlabel=submitlabel,
     )
     if tf[0] == 0:
-        if ue and ue.modules.count():
+        if ue and ue.modules.count() and ue.semestre_idx is not None:
             modules_div = f"""<div id="ue_list_modules">
             <div><b>{ue.modules.count()} modules sont rattachés
             à cette UE</b> du semestre S{ue.semestre_idx},