Index: wp-includes/ms-functions.php
===================================================================
--- wp-includes/ms-functions.php	(revision 20537)
+++ wp-includes/ms-functions.php	(working copy)
@@ -1894,7 +1894,8 @@
  */
 function welcome_user_msg_filter( $text ) {
 	if ( !$text ) {
-		return __( 'Dear User,
+		remove_filter( 'site_option_welcome_user_email', 'welcome_user_msg_filter' );
+		$text = __( 'Dear User,
 
 Your new account is set up.
 
@@ -1906,6 +1907,7 @@
 Thanks!
 
 --The Team @ SITE_NAME' );
+		update_site_option( 'welcome_user_email', $text );
 	}
 	return $text;
 }