diff --git a/GarbageCollect.php b/GarbageCollect.php
index 548ddfc..d77698d 100644
--- a/GarbageCollect.php
+++ b/GarbageCollect.php
@@ -34,7 +34,7 @@ public static function dropOldFiles($directory, $days = 30, $verbose = false)
             return false;
         }
 
-        while ($file = readdir($dir)) {
+        while (false !== ($file = readdir($dir))) {
             if ($file == '.' || $file == '..') {
                 continue;
             }