I have received 51 bug reports since April this year about crashes and hangs during mark_object, which always seems to be in very deep or infinite recursion. Apart from that, I haven't spotted a pattern, but I would be happy to forward an archive of all those reports. I can ask the user to run a different build that will give line numbers in the call stack if that would be helpful. The build in question is based on a very recent version of Emacs 23 (from the repository). Begin forwarded message: > From: "Murphy, Kevin" > Date: September 6, 2011 11:28:51 AM EDT > To: "aquamacs-bugs@aquamacs.org" > Subject: [Aquamacs-bugs] 23.3.50; Aquamacs 2.3a hangs sporadically; must be force-quit > Reply-To: Bug reports for Aquamacs Emacs > > Once or twice a day, Aquamacs 2.3a becomes unresponsive, and I have to force-quit it. I do not know how to reproduce the problem. I do not have any problems with any other apps on my (newish, pimped) iMac. I usually have up to a dozen local file buffers and a half dozen shell buffers open. I I'm using Mac OS X 10.6.8. I have some locally installed el scripts that are shadowing built-ins; I'll try disabling those for the heck of it. > > Attached is the crash log that my Mac wanted to send to Apple. The call stack looks very deep and odd, but I don't know anything about the ways of emacs. >