diff --git a/product/ERP5Type/ERP5Type.py b/product/ERP5Type/ERP5Type.py
index b9c23784b4e173e4b4a147b93f059e56da3545b2..0d6fe8af75b5f2c6207b022adc3973dd9148ea96 100644
--- a/product/ERP5Type/ERP5Type.py
+++ b/product/ERP5Type/ERP5Type.py
@@ -439,7 +439,13 @@ class ERP5TypeInformation(XMLObject,
         if init_script and init_script.startswith('add'):
           base = init_script[3:]
           # and of course migrate the property
-          self.setTypeClass(base)
+          try:
+            self.setTypeClass(base)
+          except KeyError:
+            # Unfortunately, the above setter may trigger an interaction,
+            # but the interaction workflow may not be present yet at the
+            # bootstrap time, thus simply ignore such an error for now.
+            pass
       return base
 
     security.declareProtected(Permissions.AccessContentsInformation,