diff --git a/library/Icinga/Application/Config.php b/library/Icinga/Application/Config.php
index 159af1adc..80fe3b87c 100644
--- a/library/Icinga/Application/Config.php
+++ b/library/Icinga/Application/Config.php
@@ -3,6 +3,7 @@
 
 namespace Icinga\Application;
 
+use Icinga\Exception\NotWritableError;
 use Iterator;
 use Countable;
 use LogicException;