diff --git a/app/code/community/Nexcessnet/Turpentine/Model/Observer/Varnish.php b/app/code/community/Nexcessnet/Turpentine/Model/Observer/Varnish.php
index <HASH>..<HASH> 100644
--- a/app/code/community/Nexcessnet/Turpentine/Model/Observer/Varnish.php
+++ b/app/code/community/Nexcessnet/Turpentine/Model/Observer/Varnish.php
@@ -65,7 +65,8 @@ class Nexcessnet_Turpentine_Model_Observer_Varnish extends Varien_Event_Observer
      */
     public function fixCmRedisSessionLocks($eventObject) {
         if (Mage::helper('core')->isModuleEnabled('Cm_RedisSession')) {
-            if ( ! empty($_COOKIE['frontend']) && 'crawler-session' == $_COOKIE['frontend']) {
+            if ( ! empty($_COOKIE['frontend']) && 'crawler-session' == $_COOKIE['frontend'] &&
+                    !defined('CM_REDISSESSION_LOCKING_ENABLED') ) {
                 define('CM_REDISSESSION_LOCKING_ENABLED', false);
             }
         }
Small fix for notice when CM_REDISSESSION_LOCKING_ENABLED is already defined
Example:
<I>-<I>-<I>T<I>:<I>:<I>:<I> ERR (3): Notice: Constant CM_REDISSESSION_LOCKING_ENABLED already defined  in /path/to/httpdocs/app/code/community/Nexcessnet/Turpentine/Model/Observer/Varnish.php on line <I>