diff --git a/hobo/agent/authentic2/provisionning.py b/hobo/agent/authentic2/provisionning.py
index b178cf3..dd89ef7 100644
--- a/hobo/agent/authentic2/provisionning.py
+++ b/hobo/agent/authentic2/provisionning.py
@@ -163,7 +163,11 @@ class Provisionning(threading.local):
             user_roles = {}
             parents = {}
             for rp in RoleParenting.objects.all():
-                parents.setdefault(rp.child.id, []).append(rp.parent.id)
+                # broken parent/child relationship can happen
+                try:
+                    parents.setdefault(rp.child.id, []).append(rp.parent.id)
+                except Role.DoesNotExist:
+                    pass
             Through = Role.members.through
             qs = Through.objects.filter(role__members__in=users).values_list('user_id', 'role_id')
             for u_id, r_id in qs: