diff --git a/openerp/tools/yaml_import.py b/openerp/tools/yaml_import.py
index 3172caac1f4..8f98573c413 100644
--- a/openerp/tools/yaml_import.py
+++ b/openerp/tools/yaml_import.py
@@ -449,10 +449,13 @@ class YamlInterpreter(object):
                     args = map(lambda x: eval(x, ctx), match.group(2).split(','))
                     result = getattr(model, match.group(1))(self.cr, SUPERUSER_ID, [], *args)
                     for key, val in (result or {}).get('value', {}).items():
-                        assert key in fg, "The returning field '%s' from your on_change call '%s' does not exist either on the object '%s', either in the view '%s' used for the creation" % (key, match.group(1), model._name, view_info['name'])
-                        record_dict[key] = process_val(key, val)
-                        #if (key in fields) and record_dict[key] == process_val(key, val):
-                        #    print '*** You can remove these lines:', key, val
+                        if key in fg:
+                            record_dict[key] = process_val(key, val)
+                        else:
+                            _logger.warning("The returning field '%s' from your on_change call '%s'"
+                                            " does not exist either on the object '%s', either in"
+                                            " the view '%s'",
+                                            key, match.group(1), model._name, view_info['name'])
                 else:
                     nodes = list(el) + nodes
         else: