-

diff --git a/lib/galaxy/web/framework/webapp.py b/lib/galaxy/web/framework/webapp.py
index bd2dc9e..331538e 100644
--- a/lib/galaxy/web/framework/webapp.py
+++ b/lib/galaxy/web/framework/webapp.py
@@ -390,7 +390,7 @@ class GalaxyWebTransaction( base.DefaultWebTransaction,
                     # No user, associate
                     galaxy_session.user = self.get_or_create_remote_user( remote_user_email )
                     galaxy_session_requires_flush = True
-                elif ((galaxy_session.user.email != remote_user_email) and
+                elif ((remote_user_email != '(null)' and galaxy_session.user.email != remote_user_email) and
                       ((not self.app.config.allow_user_impersonation) or
                       (remote_user_email not in self.app.config.admin_users_list))):
                     # Session exists but is not associated with the correct