diff --git a/base.php b/base.php
index 066937d1..ad90ffb8 100644
--- a/base.php
+++ b/base.php
@@ -49,6 +49,7 @@ defined('APP_MODE') or define('APP_MODE', function_exists('saeAutoLoader') ? 'sa
 // 环境常量
 define('IS_CGI', strpos(PHP_SAPI, 'cgi') === 0 ? 1 : 0);
 define('IS_WIN', strstr(PHP_OS, 'WIN') ? 1 : 0);
+define('IS_MAC', strstr(PHP_OS, 'Darwin') ? 1 : 0);
 define('IS_CLI', PHP_SAPI == 'cli' ? 1 : 0);
 define('IS_AJAX', (isset($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') ? true : false);
 define('NOW_TIME', $_SERVER['REQUEST_TIME']);
diff --git a/library/think/Loader.php b/library/think/Loader.php
index 3baf8868..dd638f37 100644
--- a/library/think/Loader.php
+++ b/library/think/Loader.php
@@ -61,7 +61,7 @@ class Loader
             if (is_file($filename)) {
                 // 开启调试模式Win环境严格区分大小写
                 if (APP_DEBUG && IS_WIN && false === strpos(realpath($filename), $class . EXT)) {
-                    return;
+                    return false;
                 }
                 // 记录加载信息
                 APP_DEBUG && self::$load[] = $filename;