--- a/src/main_window.cc
+++ b/src/main_window.cc
@@ -488,7 +488,7 @@
 {
     Glib::RefPtr<Gtk::TextBuffer> buffer = main_window_output->get_buffer();
     Gtk::TextIter end = buffer->end();
-    buffer->insert(buffer->end(),text->c_str());
+    buffer->insert(buffer->end(),Glib::convert (text->c_str(), "UTF-8", "ISO-8859-1"));
 } 
 
 void main_window::set_ui_running(bool running)