diff --git a/src/pocketmine/Server.php b/src/pocketmine/Server.php
index 0041adab6..c5c8c3483 100644
--- a/src/pocketmine/Server.php
+++ b/src/pocketmine/Server.php
@@ -155,7 +155,7 @@ class Server{
 	 *
 	 * @var int
 	 */
-	private $tickCounter;
+	private $tickCounter = 0;
 	private $nextTick = 0;
 	private $tickAverage = [20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20];
 	private $useAverage = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];