diff --git a/openupgradelib/openupgrade.py b/openupgradelib/openupgrade.py
index ece34af4..078d4014 100644
--- a/openupgradelib/openupgrade.py
+++ b/openupgradelib/openupgrade.py
@@ -86,7 +86,7 @@ def __exit__(self, exc_type, exc_value, traceback):
         many2many = core.osv.fields.many2many
         one2many = core.osv.fields.one2many
 
-    WarningError = core.exceptions.Warning
+    WarningError = core.exceptions.UserError
     if version_info[0] >= 7:
         plaintext2html = tools.mail.plaintext2html
     if version_info[0] >= 8: