> I sincerely hope that question is more addressed to Eli than to me, as I > have no idea. Don't worry, it was only a rhetoric question. > I'm more than happy to run with different breakpoints > and/or debugging code inserted. The attached is an attempt to catch the condition where the selected window's buffer is dead in a couple of strategic places. Please run with it in an unoptimized Emacs and wait till an assertion triggers. Yet another shot in the dark but I have no better idea. And if you still have the old session in the debugger, please tell us what the value of old_selected_window is. Thanks, martin