diff --git a/phpBB/install/database_update.php b/phpBB/install/database_update.php
index d33dbc5610..b1ee9b8388 100644
--- a/phpBB/install/database_update.php
+++ b/phpBB/install/database_update.php
@@ -2117,7 +2117,12 @@ function change_database_data(&$no_updates, $version)
 
 		// Changes from 3.0.9 to 3.0.10-RC1
 		case '3.0.9':
-			set_config('email_max_chunk_size', '50');
+			if (!isset($config['email_max_chunk_size']))
+			{
+				set_config('email_max_chunk_size', '50');
+			}
+
+			$no_updates = false;
 		break;
 
 		// Changes from 3.1.0-dev to 3.1.0-A1