The default mode for the unit when it has only a power cable connected to it is to go into the "point of sale Simulator mode"...This is so that when no buttons are pressed after two minutes or when the unit is powered down that the unit will rest the menus to certain predefined settings to show the product off to John Q. Public.

The ‘forced’ Simulator mode...found by pressing the MENU button during the splash screen, is for practice using the unit and making changes to the Nav Data, viewing mapping information and making menu settings changes and having all of this remembered or retained by the unit when the unit is powered off.