After two weeks of use, Robert Blumenkranz was unable to get his copy of SoundJam Free to communicate with his Rio 500 via the U

Also note this advice from the Rio FAQ page: "Question: When I turn on my Rio with it connected to my Mac, I get a message saying that the software needed to use the RioPort compatible player cannot be found. What's wrong? Answer: Make sure that the computer was restarted after installing SoundJam. The USBRioDriver must be enabled in order for the Macintosh to talk to the RioPort compatible player. Once the extension is installed, the computer must be restarted for the extension to be made active."