diff --git a/TsinghuaNet/MainViewModel.vb b/TsinghuaNet/MainViewModel.vb
index 2e3e085..30f0546 100644
--- a/TsinghuaNet/MainViewModel.vb
+++ b/TsinghuaNet/MainViewModel.vb
@@ -182,6 +182,13 @@ Class MainViewModel
         helper.Username = Username
         helper.Password = Password
     End Sub
+
+    Public Sub DisposeHelpers()
+        net?.Dispose()
+        auth4?.Dispose()
+        auth6?.Dispose()
+        usereg?.Dispose()
+    End Sub
 End Class
 
 Enum NetState
diff --git a/TsinghuaNet/MainWindow.xaml.vb b/TsinghuaNet/MainWindow.xaml.vb
index d44bac3..5092130 100644
--- a/TsinghuaNet/MainWindow.xaml.vb
+++ b/TsinghuaNet/MainWindow.xaml.vb
@@ -210,6 +210,7 @@ Class MainWindow
         log.Save()
         Notify.Visible = False
         Notify.Dispose()
+        Model.DisposeHelpers()
     End Sub
     Private Sub MainWindow_StateChanged(sender As Object, e As EventArgs) Handles Me.StateChanged
         If Me.WindowState = WindowState.Minimized Then