diff --git a/sanity_check.php b/sanity_check.php
index 17937a3f724b546f5d7977d157362a2db4deed31..e518a8c269a1514d5a8c543b76025bbe111e49de 100644
--- a/sanity_check.php
+++ b/sanity_check.php
@@ -151,6 +151,10 @@
 		$err_msg = "PHP: DOMDocument extension not found.";
 	}
 
+	if (!ISCONFIGURED) {
+		$err_msg = "config: please read config.php completely.";
+	}
+
 	if ($err_msg) {
 		print "<b>Fatal Error</b>: $err_msg\n";
 		exit;