Had trouble turning off demo mode on my MY400LMT I stuck a pin in the small hole on the rear of the unit near the power cable input. This reset the unit. Went into main menu, into settings, and turned it off that way. Hope this helps.
My MY580 is also in demo mode. This must be one of the developers showing his or her sense of humour.
Also : tried to register the unit. 10 items to fill in, unit, day of purchase, serial number, etc. The program keeps
saying that the serial number is incorrect, (but after 7 attempts you would think I got at least one attempt correct) and wipes out all the carefully entered answers except your name and your email address.
What a fun product.