It's one of these indeterminate-aborts-time again :-) Program is compiled on 68040 Powerbook MacOS 7.6.1 works fine. Same program on B&W G3 MacOS 8.5.1 - nasty abort. The program after being transfered has its PG components refreshed and a complete recompile using a "refreshed" version of StazExtras (to ensure no corruption there). The key problem seems to be reading three files consecutively from disk. All three files are the same type and use the same input routine. File 1 - read in, no abort File 2 - read in, no abort File 3 - read in - abort on the menu command or anything else that touches memory. Possibly a random memory problem, but the abort is consistant no matter where I move the code. The data reads information into arrays. I can't see how the routines can overwrite data outside of their area. The reads occur in _nullevent time and are even separted by different null events. The differnt machines may have dfferent FBII preferences set, I've changed the "number of files open" parameter but nothing else seems relevant. Anybody else had similar problems reading in data? I use PG, btw, if that's relevant. Andy