Reset clears all data and resets 3ds Max settings (viewport configuration, snap settings, Material Editor, background image, and so on). Resetting restores the startup defaults, saved in the file maxstart.max, and removes any customization you might have done during the current session.
Resetting has the same effect as exiting and restarting 3ds Max.
Resetting 3ds Max also affects the template you used to open the scene: The template is reset back to its default settings.