You could try to copy the MapSettings.cfg. When I look at that file with notepad I see my favorites. But I think this file keeps more settings, like Home address and other settings.
Slightly off topic but a lot of people have complained of losing favourites when map updating, you don't get fair warning from tt either. I found this out by doing a search where others have had the same problem. There were weird and wacky ways of fixing prob but I had not done a back up for a few days so was able to retrieve favourite from a file before the map update.