diff --git a/code/SiteTreeSubsites.php b/code/SiteTreeSubsites.php
index 9feecfe..a7f74c3 100644
--- a/code/SiteTreeSubsites.php
+++ b/code/SiteTreeSubsites.php
@@ -251,6 +251,7 @@ class SiteTreeSubsites extends SiteTreeDecorator {
 	}
 	
 	function alternateSiteConfig() {
+		if(!$this->owner->SubsiteID) return false;
 		$sc = DataObject::get_one('SiteConfig', 'SubsiteID = ' . $this->owner->SubsiteID);
 		if(!$sc) {
 			$sc = new SiteConfig();