Martin> I crashed like this in xemacs-21.2.28. No C stack available. And here is my crash on with xemacs-21.2.28 System: WinNT 4.0/SP3 Cygwin B20.1 with egcs-2.91.66 - cygwin1.dll - cygwin1-19990929.dll.gz - everything mounted binary, - CYGWIN = tty title binmode ntea nontsec vzell:/gnu/src/xemacs-21.2.28/src> Fatal error: assertion failed, file redisplay.c, line 7564, abort() Fatal error (6). Your files have been auto-saved. Use `M-x recover-session' to recover them. If you have access to the PROBLEMS file that came with your version of XEmacs, please check to see if your crash is described there, as there may be a workaround available. Otherwise, please report this bug by running the send-pr script included with XEmacs, or selecting `Send Bug Report' from the help menu. As a last resort send ordinary email to `crashes(a)xemacs.org&#39;. *MAKE SURE* to include the information in the command M-x describe-installation. If at all possible, *please* try to obtain a C stack backtrace; it will help us immensely in determining what went wrong. To do this, locate the core file that was produced as a result of this crash (it's usually called `core' and is located in the directory in which you started the editor, or maybe in your home directory), and type gdb /gnu/src/xemacs-21.2.28/src/xemacs.exe core then type `where' when the debugger prompt comes up. (If you don't have GDB on your system, you might have DBX, or XDB, or SDB. A similar procedure should work for all of these. Ask your system administrator if you need more help.) Lisp backtrace follows: event-window(#<motion-event 398, 586>) # bind (frame event) default-mouse-motion-handler(#<motion-event 398, 586>) # (condition-case ... . error) # (catch top-level ...) 0 0 [sig] D:\gnu\src\xemacs-21.2.28\src\xemacs.exe 1014 stackdump: Dumping stack trace to xemacs.exe.stackdump [1]+ Aborted ./xemacs.exe Ciao Volker