Thanks. Assuming you meant that the driver is sensitive to the extension used, I renamed the write image to foobar.dsk (and I selected 16-sector disk image format to write to) but I'm still getting a 0-byte-length image result after hitting escape to exit mame. I take it then that if I'm reading from a .woz source, mame will try to write to a destination file in .woz format regardless of any other factors?