--- a/sites/all/modules/privatemsg/privatemsg.module
+++ b/sites/all/modules/privatemsg/privatemsg.module
@@ -383,7 +383,7 @@ function privatemsg_thread_load($thread_id, $account = NULL, $start = NULL) {
       $threads[$account->uid][$thread_id] = $thread;
     }
 
-    return $threads[$account->uid][$thread_id];
+    return (array)$threads[$account->uid][$thread_id];
   }
   return FALSE;
 }