YES! I finally managed to fix this elusive memory corruption bug, that showed up on a couple of Solaris and HPUX builds. Akiumi Hasegawa graciously provided an account on his machine for me to debug this -- Thanks Aki! The problem was that we didn't allocate enough space for the argv[] array used for run_temacs -- somebody forgot about the trailing 0. This bug must have been there for AGES! It showed up so seldomly because DO_REALLOC doubles the existing size. In this case it will only show up when nargs=2^n-1. This also proves that all good bug-fixes are one-liners. :-) The patch is against the 21.2.13 release. This is definitely recommended for 21.1 Gunnar 1999-05-11 Gunnar Evermann <ge204(a)eng.cam.ac.uk&gt; * emacs.c (Frun_emacs_from_temacs): (re)alloc natgs+2 entries for run_temacs_argv array -- fixes random memory corruption crash Index: src/emacs.c =================================================================== RCS file: /usr/CVSroot/XEmacs/xemacs/src/emacs.c,v retrieving revision 1.82.2.10 diff -u -r1.82.2.10 emacs.c --- emacs.c 1999/03/03 16:38:47 1.82.2.10 +++ emacs.c 1999/05/11 21:40:36 ＠＠ -2014,7 +2014,7 ＠＠ total_len += wampum_all_len[ac]; } DO_REALLOC (run_temacs_args, run_temacs_args_size, total_len, char); - DO_REALLOC (run_temacs_argv, run_temacs_argv_size, nargs+1, char *); + DO_REALLOC (run_temacs_argv, run_temacs_argv_size, nargs+2, char *); memcpy (run_temacs_args, wampum, namesize); run_temacs_argv [0] = run_temacs_args;