diff --git a/src/pocketmine/MemoryManager.php b/src/pocketmine/MemoryManager.php
index 4208d5fb1..1b77c70e3 100644
--- a/src/pocketmine/MemoryManager.php
+++ b/src/pocketmine/MemoryManager.php
@@ -217,7 +217,7 @@ class MemoryManager{
 
 	public function dumpServerMemory($outputFolder, $maxNesting, $maxStringSize){
 		$hardLimit = ini_get('memory_limit');
-		ini_set('memory_limit', -1);
+		ini_set('memory_limit', '-1');
 		gc_disable();
 
 		if(!file_exists($outputFolder)){