diff --git a/ordernumber.script.php b/ordernumber.script.php
index 2cfd86cca81a387c52963622daf1e9d5a8a45837..00905c16035de2d92c43ce6b3d10e20f05625d27 100644
--- a/ordernumber.script.php
+++ b/ordernumber.script.php
@@ -80,6 +80,11 @@ class plgVmShopperOrdernumberInstallerScript
     public function update(JAdapterInstance $adapter)
     {
         $db = JFactory::getDBO();
+        $tbl = $db->setQuery('SHOW TABLES like "#__virtuemart_shopper_plg_ordernumber";')->loadObject();
+        if (!$tbl) {
+            return true;
+        }
+
         $db->setQuery('ALTER TABLE `#__virtuemart_shopper_plg_ordernumber` CHANGE `number_type` `number_type` VARCHAR(30) NULL DEFAULT NULL;');
         $db->query();
         
@@ -115,4 +120,4 @@ class plgVmShopperOrdernumberInstallerScript
         $db->setQuery('DROP TABLE IF EXISTS `#__virtuemart_shopper_plg_ordernumber`;');
         $db->query();
     }
-}
\ No newline at end of file
+}