Yes. Make a full backup using Explorer, not Home. Ensure hidden files/folders are showing.
Then update your firmware and then, in Home: Tools-->Latest Map guarantee. You have 30 days from first use to get it.
Then ANOTHER full backup using Explorer.
Maybe I'm missing something, but other than your preferences, favorites, etc.. why does everyone insist that the backup is super important?
I had a corrupted OS on my TomTom a while back, and rather than restore a backup (which I certainly could have done) I let TT Home download and re-install the firmware and the map that was on my account.
You can, from what I understand, re-download the map that you paid for as often as you like.
In fact, you can go to TT in your explorer, delete every file on it.. then hook to TT home and it will fix it. At least that has been my experience.
Am I missing something?