diff --git a/wp-includes/canonical.php b/wp-includes/canonical.php
index 0bf5080129..600d881751 100644
--- a/wp-includes/canonical.php
+++ b/wp-includes/canonical.php
@@ -4,7 +4,7 @@
 function redirect_canonical($requested_url=NULL, $do_redirect=true) {
 	global $wp_rewrite, $posts, $is_IIS;
 
-	if ( is_feed() || is_trackback() || is_search() || is_comments_popup() || is_admin() || $is_IIS || ( isset($_POST) && count($_POST) ) )
+	if ( is_feed() || is_trackback() || is_search() || is_comments_popup() || is_admin() || $is_IIS || ( isset($_POST) && count($_POST) ) || is_preview() )
 		return;
 
 	if ( !$requested_url ) {