diff --git a/bin/addons/base/ir/ir_actions.py b/bin/addons/base/ir/ir_actions.py
index e76799024ef..7a479344e18 100644
--- a/bin/addons/base/ir/ir_actions.py
+++ b/bin/addons/base/ir/ir_actions.py
@@ -177,7 +177,7 @@ class act_window(osv.osv):
 
                 if 'calendar' not in modes:
                     mobj = self.pool.get(act.res_model)
-                    if mobj._date_name in mobj._columns:
+                    if hasattr(mobj, '_date_name') and mobj._date_name in mobj._columns:
                         res[act.id].append((False, 'calendar'))
         return res