SATMan

I did get to exactly the same position, when I wrote the following post. I was also pulling my hair out until I tried the commands below. Can I just add that if you copy the new files over the old (without delete and definitely without re-format) there is also the chance on a MAC of getting other hidden files lying around on the media, which leads to the Nav working, but blank squares for road names and places. What's needed (from another forum) is the following: find /Volumes/<your-volume-name> -name '._*' -type f -delete With the WARNING that you should run without the "-delete" first just to check you truly are pointed as the SSD card and not your main hard-drive!! Doing this creates new hidden files in the root of the media, so you need to re-run the original command above (rm -Rf ...) to remove those before whipping the sd-card out.

One other item - it's important if you get to deleting the hidden files that you pull the SD card out afterwards rather than ejecting from 'Finder', since the eject will only write back the files you've just deleted. It's worth a double check afterwards with the write-protect switched on the SD card to make sure there are no other hidden files that have slipped back on! ;-)

It probably is the hidden files causing the problem - from a terminal window run the following: $ cd /Volumes $ ls $ cd /Volumes/<your-volume-name> $ ls -aux At least then you can do as much as possible to make sure you are looking at the right volume and can look for any hidden files that you may not be seeing in 'Finder' It may well be good to get a MAC-savy friend to double-ensure you don't delete the entire hard drive......it wouldn't make for a good day! ;-)

Can only suggest copying all the files across, since if it's a genuine card that has worked before then it should at least get to the validating stage. I can only assume the Amunsen is looking for a file that you don't have on the disk and existing with the error, even then I'd have thought you might see the validating icon before the 'not valid nav data' since that is definitely the error I get when I put the wrong media into the unit....is it really the SD-card you think it is!?

Can I just add that if you copy the new files over the old (without delete and definitely without re-format) there is also the chance on a MAC of getting other hidden files lying around on the media, which leads to the Nav working, but blank squares for road names and places. What's needed (from another forum) is the following: find /Volumes/<your-volume-name> -name '._*' -type f -delete With the WARNING that you should run without the "-delete" first just to check you truly are pointed as the SSD card and not your main hard-drive!! Doing this creates new hidden files in the root of the media, so you need to re-run the original command above (rm -Rf ...) to remove those before whipping the sd-card out.