diff --git a/wiki-common/lib/init.php b/wiki-common/lib/init.php
index b44271db..6ba08c0c 100644
--- a/wiki-common/lib/init.php
+++ b/wiki-common/lib/init.php
@@ -48,6 +48,10 @@
 
 define('REMOTE_ADDR', isset($_SERVER['HTTP_CF_CONNECTING_IP']) ? $_SERVER['HTTP_CF_CONNECTING_IP'] : $_SERVER['REMOTE_ADDR']);
 
+if (class_exists('PDO')){
+	die('PukiWiki Adv. requires PDO.');
+}
+
 // Load Bad-behavior
 if (file_exists(VENDOR_DIR . 'bad-behavior' . DIRECTORY_SEPARATOR . 'bad-behavior-sqlite.php') ){
 	require( VENDOR_DIR . 'bad-behavior' . DIRECTORY_SEPARATOR . 'bad-behavior-sqlite.php');