diff --git a/core/default_settings/default_setting_edit.php b/core/default_settings/default_setting_edit.php
index 076a5f14fd..1bdb4040d9 100644
--- a/core/default_settings/default_setting_edit.php
+++ b/core/default_settings/default_setting_edit.php
@@ -80,8 +80,12 @@
 	}
 
 //sanitize the variables
-	$search = preg_replace('#[^a-zA-Z0-9_\-\. ]#', '', $search);
-	$default_setting_category = preg_replace('#[^a-zA-Z0-9_\-\. ]#', '', $default_setting_category);
+	if (!empty($search)) {
+		$search = preg_replace('#[^a-zA-Z0-9_\-\. ]#', '', $search);
+	}
+	if (!empty($domain_setting_category)) {
+		$default_setting_category = preg_replace('#[^a-zA-Z0-9_\-\. ]#', '', $default_setting_category);
+	}
 
 //build the query string
 	$query_string = '';