Hello Roger, do you have gdb on your system ? I'm not sure if it comes standard with OS X, or whether it's only installed with the development tools. Try running it from a command line. "quit" will get you out of it. If you do have it, can I send you a version of the dispwin with debugging symbols in it, so you can run it and report a stack backtrace. This will give me a clue as to what system call it's failing in. Graeme.