Index: wp-admin/includes/media.php
===================================================================
--- wp-admin/includes/media.php	(revision 21259)
+++ wp-admin/includes/media.php	(working copy)
@@ -1064,7 +1064,7 @@
 	$toggle_on  = __( 'Show' );
 	$toggle_off = __( 'Hide' );
 
-	$filename = esc_html( basename( $post->guid ) );
+	$filename = esc_html( end( explode( '/', $post->guid ) ) );
 	$title = esc_attr( $post->post_title );
 
 	if ( $_tags = get_the_tags( $attachment_id ) ) {