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Cannot authenticate maps!!! on Zumo 660 LM

I have a zumo 660 LM and I downloaded North america NT 2013.30 3D US & Canada and also 2013.30 regular. When I start the GPS the following message shows up: "CANNOT AUTHENTICATE MAPS'' What have i done wrong. Any advise or help would be appreciated Thanks


  • t923347 413 Points
    If you downloaded 2013.30 twice and only have Lifetime Maps for a single device, that could possibly be your problem as each device is only eligible for a single map update every update cycle.

    I'm not sure which map version the Zumo uses but it will either be North america NT 2013.30 3D US & Canada OR 2013.30 regular (whatever that is???) but you can't use both.

    In theory, if you downloaded and installed 2013.30 once and then downloaded and installed it again, the second install should have overwritten the first one, but as you seem to have downloaded 2 different types of the same maps I can only assume that this has something to do with your current problem.
  • sussamb 764 Points
    As well as that advice note that you will get the message "can't authenticate map", when the *.gma file is missing. If you do only have one map loaded, and no corresponding .gma file then it can be downloaded from your myGarmin account.

    1) Log into your myGarmin account.
    2) Click on the myMaps tab.
    3) Find your GPS in the list and click on the details link to the right of the image of your device.
    4) Find and copy the Product Key for your map product.
    5) Connect your GPS to the computer.
    6) At the top right of the page there's a "Unlock On the Road/Trail Maps" link. Click on that. You'll be taken to a "Unlock Maps" page.
    7) Scroll to the bottom of that page. You'll see a section like this RetrieveUnlocks.png with the Unit ID field filled in.

    Enter the "Device Serial Number" and the "Product Key/Coupon Code" (from 4)) and then click the "Retrieve Unlocks" button.

    That will (re)create the GMA and UNL files on your device.
  • alanb 419 Points
    Excellent post sussamb!. Maybe this thread should be added to the "Update your maps, firmware, ..." sticky.
  • Boyd 1853 Points
    Good idea - it has been added. :)
  • class3 52 Points
    I think your best shot is to re-download and re-install the maps, preferably through MapUpdater instead of Lifetime Map Updater. This solution worked for this individual:
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