I just purchased a 595lm. I have basecamp loaded on my MacBook Pro and I get the subject message when I plug into the USB port. Sometimes there is no problem but most of the time I get this message. Apple has looked at the computer and assures me that it is ok. The MacBook is about 5 years old but I have never had any problems with any other plug-ins. Had a couple of conversations with Garmin support but not very impressed with the people with whom I spoke.