I have a 600T and when I try to synch it with either my Mac or PC it crashes. I have all of the updated software. Mac platform seems more unstable than PC. I get messages that there isn't room for JNX files and then things crash. I think that JNX are birdseye. I find birdseye to be totally useless here in Alaska. The detail in way less than Google maps. I wish I could totally eliminate birdseye and not get all of the birdseye prompts.