one xl no maps found

Hi there ppl,
been a while since i posted, anyway here's the problem. I bought a second hand one xl with western europe map. Everything is ok, but when i connect to tomtom home and update, when it's finished and restarts it says no maps found. I then restore backup and maps are found. Why is this happening? home recommends the update

[mikealder]

Download and run the clear flash utility which is available from the tomtom web site - Mike

Tried that with same result