diff --git a/trytond/trytond/convert.py b/trytond/trytond/convert.py
index 159a4c3785..da696ae277 100644
--- a/trytond/trytond/convert.py
+++ b/trytond/trytond/convert.py
@@ -595,6 +595,8 @@ class TrytondXmlHandler(sax.handler.ContentHandler):
             if new_values:
                 to_update += [[record], values]
             if values.keys() - set(mdata.field_names):
+                if mdata.id is None:
+                    mdata.save()
                 field_names = dict(mdata.get_field_names()).keys()
                 mdata.field_names = tuple(
                     (set(mdata.field_names) & field_names) | values.keys())