diff --git a/plugins/libkolab/lib/kolab_format.php b/plugins/libkolab/lib/kolab_format.php
index d00d5ee4..814800d2 100644
--- a/plugins/libkolab/lib/kolab_format.php
+++ b/plugins/libkolab/lib/kolab_format.php
@@ -528,6 +528,7 @@ abstract class kolab_format
             $created = $object['created'] ?: new DateTime('now');
             $created->setTimezone(new DateTimeZone('UTC')); // must be UTC
             $this->obj->setCreated(self::get_datetime($created));
+            $object['created'] = $created;
         }
 
         $object['changed'] = new DateTime('now', new DateTimeZone('UTC'));
diff --git a/plugins/libkolab/lib/kolab_storage_cache.php b/plugins/libkolab/lib/kolab_storage_cache.php
index 3a73d982..87c0649b 100644
--- a/plugins/libkolab/lib/kolab_storage_cache.php
+++ b/plugins/libkolab/lib/kolab_storage_cache.php
@@ -893,6 +893,12 @@ class kolab_storage_cache
         $object['_size']      = strlen($sql_arr['xml']);
         $object['_formatobj'] = kolab_format::factory($format_type, 3.0, $sql_arr['xml']);
 
+        // Fix old broken objects with missing creation date
+        if (empty($object['created']) && method_exists($object['_formatobj'], 'to_array')) {
+            $new_object        = $object['_formatobj']->to_array();
+            $object['created'] = $new_object['created'];
+        }
+
         return $object;
     }