Thanks for your answers. I perfomed as Butters suggested. I cleared the nonvol but after the problem still remains. It meens whae i connect the device to the computer, open Garminexpress i seen there are several updates including maps. So to not spend to much time to update everyting i try just to update the software version from 4.10 to 5.90. After update, disconnect the device from the computer ande connect it back after 5 seconds, garminexpress shows the same update available again. The devise has not been updated. What more can i do? As just a test a added by means of the computer a map with a random textfile. After diconnect the device from teh computer an reconnect the device, i see this last added map including the text file has vanniched? exactly what happens to the maps. I still wonder what's wrong with the device.
Kind regards,
Francis.