diff --git a/code/SiteTreeSubsites.php b/code/SiteTreeSubsites.php
index d8b53c9..bdffb2d 100644
--- a/code/SiteTreeSubsites.php
+++ b/code/SiteTreeSubsites.php
@@ -224,7 +224,10 @@ class SiteTreeSubsites extends DataObjectDecorator {
 		// Generate the existing absolute URL and replace the domain with the subsite domain.
 		// This helps deal with Link() returning an absolute URL.
 		$url = Director::absoluteURL($this->owner->Link());
-		return preg_replace('/\/\/[^\/]+\//', '//' .  $this->owner->Subsite()->domain() . '/', $url);
+		if($this->owner->SubsiteID) {
+			$url = preg_replace('/\/\/[^\/]+\//', '//' .  $this->owner->Subsite()->domain() . '/', $url);
+		}
+		return $url;
 	}
 	
 }
diff --git a/code/Subsite.php b/code/Subsite.php
index 2910b74..9acd77e 100644
--- a/code/Subsite.php
+++ b/code/Subsite.php
@@ -114,6 +114,10 @@ class Subsite extends DataObject implements PermissionProvider {
 				$domain = str_replace('.www.','.', $domain);
 				return $domain;
 			}
+			
+		// SubsiteID = 0 is often used to refer to the main site, just return $_SERVER['HTTP_HOST']
+		} else {
+			return $_SERVER['HTTP_HOST'];
 		}
 	}