diff --git a/src/Generator.php b/src/Generator.php
index ee01a41e94..e605ef3112 100644
--- a/src/Generator.php
+++ b/src/Generator.php
@@ -966,8 +966,8 @@ public function __destruct()
         $this->seed();
     }
 
-    public function __wakeup()
+    public function __unserialize(array $data)
     {
-        $this->formatters = [];
+        throw new \Exception('Generator cannot be unserialized');
     }
 }