diff --git a/WebSocketTool/App.xaml.cs b/WebSocketTool/App.xaml.cs
index 806de88..c428533 100644
--- a/WebSocketTool/App.xaml.cs
+++ b/WebSocketTool/App.xaml.cs
@@ -22,12 +22,17 @@ namespace WebSocketTool
         protected override void OnStartup(StartupEventArgs e)
         {
             base.OnStartup(e);
-            LogManager.GetManager().Init("WebSocketTool");
-            XmlConfigurator.ConfigureAndWatch(new FileInfo("log4net.config"));
+            AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
             Directory.CreateDirectory("log");
+            LogManager.GetManager().Init("WebSocketTool");
             log = LogManager.GetManager().GetLog(nameof(App));
         }
 
+        private static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
+        {
+            log.Error($"app crash:{e.ExceptionObject}");
+        }
+
         public static void RunOnUIThread(Action action)
         {
             if (Current == null)
diff --git a/WebSocketTool/Util/Log.cs b/WebSocketTool/Util/Log.cs
index 44be902..57de6d1 100644
--- a/WebSocketTool/Util/Log.cs
+++ b/WebSocketTool/Util/Log.cs
@@ -104,7 +104,7 @@ namespace WebSocketTool.Util
             log.Warn(msg);
         }
 
-        public void Error(string msg, Exception e)
+        public void Error(string msg, Exception e = null)
         {
             log.Error(msg, e);
         }