I switched on my Go 5000 the other day and got the message 'no maps found - please install a map' or similar. I plugged into my computer (windows) and tried to update via MyDrive Connect. It didn't recognize the SD card in the device so I couldn't install the map (Europe). I installed a smaller map on the device. This then enabled me to access the device and reformat the card. It still wasn't recognized so I did a factory reset. Finally the card was seen by MyDrive and I went to install the Europe map on the card. It downloaded, Went all the way through the update process but then I got the message 'update failed'. So far I have tried:
Retrying the update
Clearing the cache in MyDrive and updating again
A different SD card
Another factory reset.
Always the same 'update failed' message.