Index: wp-includes/admin-bar.php
===================================================================
--- wp-includes/admin-bar.php	(revision 18947)
+++ wp-includes/admin-bar.php	(working copy)
@@ -768,7 +768,7 @@
  */
 function wp_admin_bar_search_menu( $wp_admin_bar ) {
 	$form  = '<div id="adminbarsearch-wrap">';
-	$form .= '<form action="' . home_url() . '" method="get" id="adminbarsearch">';
+	$form .= '<form action="' . home_url( '/' ) . '" method="get" id="adminbarsearch">';
 	$form .= '<input class="adminbar-input" name="s" id="adminbar-search"';
 	$form .= 'type="text" value="" maxlength="150" placeholder="' . esc_attr__( 'Search' ) . '" />';
 	$form .= '<input type="submit" class="adminbar-button" value="' . __('Search') . '"/>';