--- modules/user.module.orig	2006-08-02 20:13:28.000000000 +0200
+++ modules/user.module	2006-09-19 10:43:00.000000000 +0200
@@ -114,7 +114,7 @@ function user_save($account, $array = ar
         $v[] = md5($value);
       }
       else if ((substr($key, 0, 4) !== 'auth') && ($key != 'pass')) {
-        if (in_array($key, $user_fields)) {
+        if ($value !== NULL && in_array($key, $user_fields)) {
           // Save standard fields
           $query .= "$key = '%s', ";
           $v[] = $value;