Thread: "Cannot authenticate maps" on a previously working mapset

Is this something that would happen out of the blue on a working mapset though. ... It worked for several months and now just started doing this.

Did you recently update the firmware on the unit. If you hooked up to Garmins servers it will do it automatically. Or if you updated Mapsource or other software from Garmin it will update firmware and make ther GMA protection start to work again.

You can try re-installing all of the "Patched" programs such as MapSource and see if that works.