Hi Timo, Could you please add some additional informations (as root) : * ldd /usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1 | grep gtk * find /usr/lib -name '*gtk*.so*' -exec nm --print-file-name --dynamic {} \; | grep gtk_level_bar_get_type * dpkg -l libgtk* Thanks, -- Léo