diff --git a/htdocs/core/class/conf.class.php b/htdocs/core/class/conf.class.php
index 957bec47088..378d831861f 100644
--- a/htdocs/core/class/conf.class.php
+++ b/htdocs/core/class/conf.class.php
@@ -204,7 +204,16 @@ class Conf
 		// If you can't set timezone of your PHP, set this constant. Better is to set it to UTC.
 		// In future, this constant will be forced to 'UTC' so PHP server timezone will not have effect anymore.
 		//$this->global->MAIN_SERVER_TZ='Europe/Paris';
-		if (! empty($this->global->MAIN_SERVER_TZ) && $this->global->MAIN_SERVER_TZ != 'auto') date_default_timezone_set($this->global->MAIN_SERVER_TZ);
+		if (! empty($this->global->MAIN_SERVER_TZ) && $this->global->MAIN_SERVER_TZ != 'auto')
+		{
+			try {
+				date_default_timezone_set($this->global->MAIN_SERVER_TZ);
+			}
+			catch(Exception $e)
+			{
+				dol_syslog("Error: Bad value for parameter MAIN_SERVER_TZ=".$this->global->MAIN_SERVER_TZ, LOG_ERR);
+			}
+		}
 
 		// Object $mc
 		if (! defined('NOREQUIREMC') && ! empty($this->multicompany->enabled))