diff --git a/classmap.php b/classmap.php
index a12636cc..7f3bc7fb 100644
--- a/classmap.php
+++ b/classmap.php
@@ -75,11 +75,9 @@ return [
     'think\Hook'                                => CORE_PATH . 'Hook' . EXT,
     'think\Lang'                                => CORE_PATH . 'Lang' . EXT,
     'think\Log'                                 => CORE_PATH . 'Log' . EXT,
-    'think\log\driver\Browser'                  => CORE_PATH . 'log' . DS . 'driver' . DS . 'Browser' . EXT,
     'think\log\driver\File'                     => CORE_PATH . 'log' . DS . 'driver' . DS . 'File' . EXT,
     'think\log\driver\Sae'                      => CORE_PATH . 'log' . DS . 'driver' . DS . 'Sae' . EXT,
     'think\log\driver\Socket'                   => CORE_PATH . 'log' . DS . 'driver' . DS . 'Socket' . EXT,
-    'think\log\driver\Trace'                    => CORE_PATH . 'log' . DS . 'driver' . DS . 'Trace' . EXT,
     'think\Model'                               => CORE_PATH . 'Model' . EXT,
     'think\model\Merge'                         => CORE_PATH . 'model' . DS . 'Merge' . EXT,
     'think\model\Pivot'                         => CORE_PATH . 'model' . DS . 'Pivot' . EXT,
diff --git a/library/think/Log.php b/library/think/Log.php
index 36388424..608910a0 100644
--- a/library/think/Log.php
+++ b/library/think/Log.php
@@ -10,6 +10,7 @@
 // +----------------------------------------------------------------------
 
 namespace think;
+use think\exception\ClassNotFoundException;
 
 /**
  * Class Log
@@ -53,7 +54,11 @@ class Log
         $class        = false !== strpos($type, '\\') ? $type : '\\think\\log\\driver\\' . ucwords($type);
         self::$config = $config;
         unset($config['type']);
-        self::$driver = new $class($config);
+        if(class_exists($class)) {
+            self::$driver = new $class($config);
+        } else {
+            throw new ClassNotFoundException('class not exists:' . $class, $class);
+        }
         // 记录初始化信息
         App::$debug && Log::record('[ LOG ] INIT ' . $type . ': ' . var_export($config, true), 'info');
     }