diff --git a/wp-includes/ms-functions.php b/wp-includes/ms-functions.php
index f4fe306b7d..b8453c730b 100644
--- a/wp-includes/ms-functions.php
+++ b/wp-includes/ms-functions.php
@@ -1150,10 +1150,11 @@ function install_blog($blog_id, $blog_title = '') {
 	populate_roles();
 	$wp_roles->_init();
 
+	$url = untrailingslashit( $url );
 	// fix url.
 	update_option('siteurl', $url);
 	update_option('home', $url);
-	update_option('fileupload_url', $url . "files" );
+	update_option('fileupload_url', $url . "/files" );
 	update_option('upload_path', UPLOADBLOGSDIR . "/$blog_id/files");
 	update_option('blogname', stripslashes( $blog_title ) );
 	update_option('admin_email', '');