diff --git a/system/libraries/User_agent.php b/system/libraries/User_agent.php
index 1f4b2fa..3fe2e05 100644
--- a/system/libraries/User_agent.php
+++ b/system/libraries/User_agent.php
@@ -175,7 +175,7 @@
 	 */
 	protected function _load_agent_file()
 	{
-		if (defined('ENVIRONMENT') && is_file(APPPATH.'config/'.ENVIRONMENT.'/user_agents.php'))
+		if (is_file(APPPATH.'config/'.ENVIRONMENT.'/user_agents.php'))
 		{
 			include(APPPATH.'config/'.ENVIRONMENT.'/user_agents.php');
 		}