diff --git a/endpoints/registry.py b/endpoints/registry.py
index 47d4f65ac..72633939e 100644
--- a/endpoints/registry.py
+++ b/endpoints/registry.py
@@ -370,6 +370,7 @@ def generate_ancestry(image_id, uuid, locations, parent_id=None, parent_uuid=Non
   if not parent_id:
     store.put_content(locations, store.image_ancestry_path(uuid), json.dumps([image_id]))
     return
+
   data = store.get_content(parent_locations, store.image_ancestry_path(parent_uuid))
   data = json.loads(data)
   data.insert(0, image_id)
@@ -470,8 +471,13 @@ def put_image_json(namespace, repository, image_id):
   store.put_content(repo_image.storage.locations, json_path, request.data)
 
   profile.debug('Generating image ancestry')
-  generate_ancestry(image_id, uuid, repo_image.storage.locations, parent_id, parent_uuid,
-                    parent_locations)
+
+  try:
+    generate_ancestry(image_id, uuid, repo_image.storage.locations, parent_id, parent_uuid,
+                      parent_locations)
+  except IOError as ioe:
+    profile.debug('Error when generating ancestry: %s' % ioe.message)
+    abort(404)
 
   profile.debug('Done')
   return make_response('true', 200)