Hello, As kpse.find_file can't get the path of mpost.mem, I made some experimentations and got a segmentation fault with texlua (revision 1858, on debian/sid 32 bit) on the following code: kpse.set_program_name("toto") local filename = "/var/lib/texmf/web2c/metapost/mpost.mem" function finder (name, mode, ftype) if mode == "w" then return name else local result = kpse.find_file(name,ftype) if not result and name == "mpost.mem" then result = filename end return result end end local mpx = mplib.new { ini_version = false, mem_name = "mpost.mem", find_file = finder } you have to replace filename by the true value of you mpost.mem to get the segfault. Thank you, -- Elie