diff --git a/phpgwapi/inc/class.egw_time.inc.php b/phpgwapi/inc/class.egw_time.inc.php
index 1d261fc7a0..85bdb89da7 100644
--- a/phpgwapi/inc/class.egw_time.inc.php
+++ b/phpgwapi/inc/class.egw_time.inc.php
@@ -398,10 +398,18 @@ class egw_time extends DateTime
 		if (empty($GLOBALS['egw_info']['server']['server_timezone']))
 		{
 			$config = new config('phpgwapi');
-			$config->save_value('server_timezone',
-				$GLOBALS['egw_info']['server']['server_timezone'] = date_default_timezone_get());
-			$config->save_repository();
-			error_log(__METHOD__."() stored server_timezone=".date_default_timezone_get());
+			$config->read_repository();
+			if ($config->config_data['server_timezone'])
+			{
+				$GLOBALS['egw_info']['server']['server_timezone'] = $config->config_data['server_timezone'];
+			}
+			else
+			{
+				$config->save_value('server_timezone',
+					$GLOBALS['egw_info']['server']['server_timezone'] = date_default_timezone_get());
+				$config->save_repository();
+				error_log(__METHOD__."() stored server_timezone=".date_default_timezone_get());
+			}
 		}
 		date_default_timezone_set($GLOBALS['egw_info']['server']['server_timezone']);