RNS510 destination entries wont delete /add New maps may not complete loading

(Please note this sentence does not begin with "SO" no sentence in the English language can!)

I have cured a problem where no new recent or saved destinations can be added, the latest maps doesn't confirm completion and deleting all destination entries succeeds but they all come back the next day.

The normal delete which can be found by pressing the setup button, then selecting System - factory settings- Navigation Memory and navigation asked for confirmation to delete and then did so resulting in blank lists but the next day all the old destinations would be back and recent ones I had programmed were not showing.

I had previously noticed that searching for some post codes was not possible as they did not exist .

The fix was to download the map partition reformatting tool called " 2720_mpf "  which is an ISO 

Burned to a cd as it is very small and run. you then need to re install the maps

To run 2720 put the cd you burned into the unit, it will actually run on its own but when completed will complain it needed an swl disc, it then tells you to reboot the unit by pressing the 3 button reboot ( setup mic and eject)

The error message is "software downgrade error"

the cd will then re run and ask you to confirm that you wish to proceed with the update.

Once formatted it will say" SWL success " and then a pop up message "Please insert navigation DVD"

The maps loaded and all is well, all destination entries are blank..