Following numerous customer complaints, Garmin has acknowledged the issue and released this in response:
It has come to our attention that the Garmin nüvi 7×5 series has a firmware error that is causing some devices to perform an unprompted GPS software update and in some cases shut down. Garmin is aware of this issue and we are working diligently on a solution. We know our customers rely upon their GPS devices and we apologize for any inconvenience this has caused. Developing quality products always has been and continues to be a priority at Garmin. For regular updates about this issue, please visit www.garmin.com/support.