diff --git a/odoo/tools/config.py b/odoo/tools/config.py
index 79978fd1d0c..03a08710f4f 100644
--- a/odoo/tools/config.py
+++ b/odoo/tools/config.py
@@ -711,7 +711,7 @@ class configmanager(object):
 
     def _normalize(self, path):
         if not path:
-            return path
+            return ''
         return realpath(abspath(expanduser(expandvars(path.strip()))))