On Oct 28, 2010, at 5:39 PM, Brian S wrote: > Or just check to make sure the returned mutable array ref is non-zero. The demo is sloppy code. I’ve updated the demo if you want to see it. I do this, it returns a nonvalid mutable array. I renamed a binary file in place of the file the demo writes and when it tries to read it crashes after CFArrayCreateWithContentsOfFile which returns a non-zero mutable ref.