diff --git a/lib/Controller.php b/lib/Controller.php
index 85767b12..10973aa5 100644
--- a/lib/Controller.php
+++ b/lib/Controller.php
@@ -114,7 +114,7 @@ class Controller
             error_log(I18n::_('%s requires php %s or above to work. Sorry.', I18n::_('PrivateBin'), self::MIN_PHP_VERSION));
             return;
         }
-        if (!empty(PATH) && substr(PATH, -1) !== DIRECTORY_SEPARATOR) {
+        if (!defined('PATH') || substr(PATH, -1) !== DIRECTORY_SEPARATOR) {
             error_log(I18n::_('%s requires the PATH to end in a "%s". Please update the PATH in your index.php.', I18n::_('PrivateBin'), DIRECTORY_SEPARATOR));
             return;
         }