My Montana indicates "Cannot Unlock File: D77749160A.gpi". If the Micro SD card is inserted, the Montana shuts down regardless of whether I select OK or do nothing.
If I remove the Micro SD with most of my maps, the notification still appears but it does not shut down if I select OK. Tracks and way points are recorded and can be saved using Basecamp.
Unfortunately I cannot use my Montana within of my recently purchased maps.