I have received my copy of MacTopos for Oregon. I found that it would not read on my computer and after contacting James and Associates found out that it is writen on dual layer media in the plus format. I have sent mine back and they are going to replace it with 2 single layer dvd's which my drive will be able to read. My dvd is not an original equipment dvd but was added later and is a Pioneer dvr-107d. I am using 10.2.8.