Thanks for your help ! =========== Oh? There's evidence to the contrary... =========== Oh dear .. I goofed. I did indeed build 21.1.12 on AIX 4.3.2 .. I had earlier compiled 21.1.8 on 4.2.1 (on the same machine earlier named "darwin"). Since I couldn't even start my newly built XEmacs, I started my old XEmacs (21.1.8) and did a M-x report-bug .. as a result you are seeing some crap info regarding the OS version. I can confirm that I indeed compiled XEmacs-21.1.12 on AIX 4.3.2 .. I also compiled XEmacs-21.1.8 (my earlier source tree) on 4.3.2 - in both cases I had the exact same crash in specifier.c .. I'm pretty sure the debugger backtrace is valid. I stepped through the code right to the point it dumps core. Tinkerty-tonk Sailesh -- IBM Almaden Research Center, B1-429 650 Harry Road, San Jose, CA 95120 Ph: (408) 927-1913, Tie: 457-1913, Fridays: (408) 463-4176 Internet: sailesh(a)us.ibm.com