I sold someone my copy of 10.5 on Amazon, and shipped it out to him. I get an email from this person stating that he wants his money back because I sent 10.5.4 when I listed it under 10.5.6. Obviously I didn't pay attention to that minor detail, but this guy did. He says that a 10.5.4 disc won't work on his mac pro. I can't think of a reason that would be true. Here's some of his email: Any help is greatly appreciated.