Garmin Map Download Corrupt

Bought the 49 lower state maps today from Garmin and downloaded through Garmin express onto my Zumo 590 LM. All seems ok, and I've downloaded onto the sd card and unit itself, however when powering on the Garmin it comes up with an error saying maps corrupt.

Looking in the settings the maps are shown and I can get a search to New York however I don't want to arrive in America (on Monday) to have no Garmin for our west coast road trip.

Any help or advice greatly appreciated.

I'd try a reinstall to SD card only. How have you split the download between card & device or have you loaded it twice ?
If you've put them on twice it'll be trying to read two maps at the same time.

Managed to get it sorted in the nick of time! Turns out that the memory card from my Zumo 550 was corrupt when put in the 590. Maps downloaded onto the unit itself and fixed.