diff --git a/src/slic3r/GUI/BackgroundSlicingProcess.cpp b/src/slic3r/GUI/BackgroundSlicingProcess.cpp
index 7852006c2..5708794d3 100644
--- a/src/slic3r/GUI/BackgroundSlicingProcess.cpp
+++ b/src/slic3r/GUI/BackgroundSlicingProcess.cpp
@@ -495,8 +495,15 @@ void BackgroundSlicingProcess::schedule_upload(Slic3r::PrintHostJob upload_job)
 
 void BackgroundSlicingProcess::reset_export()
 {
-	assert(! this->running());
-	if (! this->running()) {
+	bool running = true;
+	{
+		// I don't know if it's safe to let m_mutex be lock whiole doing invalidate_step.
+		// if so, please remove the braces.
+		std::unique_lock<std::mutex> lck(m_mutex);
+		running = this->running();
+		assert(!running);
+	}
+	if (!running) {
 		m_export_path.clear();
 		m_export_path_on_removable_media = false;
 		// invalidate_step expects the mutex to be locked.
diff --git a/src/slic3r/GUI/MainFrame.cpp b/src/slic3r/GUI/MainFrame.cpp
index 5cd8e4920..524c9fd1a 100644
--- a/src/slic3r/GUI/MainFrame.cpp
+++ b/src/slic3r/GUI/MainFrame.cpp
@@ -364,8 +364,6 @@ void MainFrame::update_layout()
         break;
     }case ESettingsLayout::Old:
     {
-        // don't use view_toolbar here
-        m_plater->enable_view_toolbar(false);
         //layout
         m_plater->Reparent(m_tabpanel);
         m_tabpanel->InsertPage(0, m_plater, _L("Plater"));