It has come to light that on rare occasions some data may fall foul of a bug in Perl's regex engine that causes a segmentation fault. The perl developers say: <blockquote> This ticket is for bugs related to the overflow of the OS stack during recursion in the perl regex engine. Generally they can be "worked around" by increasing the stack size by using ulimit (bash/sh/ksh/zsh) or limit (csh/tcsh). The long term plan is to rewrite the regex engine to not use the stack for recursion. </blockquote> Changing the stack size has not proven effective on the on-line version, but we are upgrading to a development version of Perl upon which the problem is less severe. The -e3 setting on the command line version of msatfinder works around the problem, but is slow.