Index: wp-includes/update.php
===================================================================
--- wp-includes/update.php	(revision 8856)
+++ wp-includes/update.php	(working copy)
@@ -176,7 +176,7 @@
 add_action( 'admin_init', '_maybe_update_plugins' );
 add_action( 'wp_update_plugins', 'wp_update_plugins' );
 
-if ( !wp_next_scheduled('wp_update_plugins') )
+if ( !defined('WP_INSTALLING') && !wp_next_scheduled('wp_update_plugins') )
 	wp_schedule_event(time(), 'twicedaily', 'wp_update_plugins');
 
 ?>