diff --git a/apps/files_encryption/files/error.php b/apps/files_encryption/files/error.php
index f925442612d632928a1c0b674f4eef16f06a8e42..b436587dfaf47492b9abb2a59ee4eebd953a8e08 100644
--- a/apps/files_encryption/files/error.php
+++ b/apps/files_encryption/files/error.php
@@ -2,6 +2,7 @@
 
 if (!isset($_)) { //also provide standalone error page
 	require_once __DIR__ . '/../../../lib/base.php';
+	require_once __DIR__ . '/../lib/crypt.php';
 
 	$l = OC_L10N::get('files_encryption');