Index: includes/bootstrap.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/bootstrap.inc,v
retrieving revision 1.463
diff -u -p -r1.463 bootstrap.inc
--- includes/bootstrap.inc	5 Jan 2011 06:23:07 -0000	1.463
+++ includes/bootstrap.inc	6 Jan 2011 01:00:34 -0000
@@ -2066,7 +2066,10 @@ function drupal_bootstrap($phase = NULL,
  */
 function drupal_get_user_timezone() {
   global $user;
-  if (variable_get('configurable_timezones', 1) && $user->uid && $user->timezone) {
+  // Do not use the timezone of the current user if the site is in maintenance
+  // because during upgrade from Drupal 6 to 7 the user's timezone was stored
+  // differently.
+  if (!defined('MAINTENANCE_MODE') && variable_get('configurable_timezones', 1) && $user->uid && $user->timezone) {
     return $user->timezone;
   }
   else {
Index: modules/simpletest/tests/upgrade/drupal-6.bare.database.php
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/upgrade/drupal-6.bare.database.php,v
retrieving revision 1.1
diff -u -p -r1.1 drupal-6.bare.database.php
--- modules/simpletest/tests/upgrade/drupal-6.bare.database.php	28 Jun 2010 02:05:47 -0000	1.1
+++ modules/simpletest/tests/upgrade/drupal-6.bare.database.php	6 Jan 2011 01:00:34 -0000
@@ -7902,7 +7902,7 @@ db_insert('users')->fields(array(
   'access' => '0',
   'login' => '0',
   'status' => '0',
-  'timezone' => NULL,
+  'timezone' => '-21600',
   'language' => '',
   'picture' => '',
   'init' => '',
@@ -7923,7 +7923,7 @@ db_insert('users')->fields(array(
   'access' => '1277671612',
   'login' => '1277671612',
   'status' => '1',
-  'timezone' => NULL,
+  'timezone' => '-21600',
   'language' => '',
   'picture' => '',
   'init' => 'admin@example.com',