When I finally managed to sync after five days of network errors, all of my data for the previous four days was gone. From what I can see, no data is saved for more than a day. I'm ready to forgive Garmin for occasional server problems, but I've tried to sync maybe 50 times over three weeks and have succeeded 3-4 times, and I always have to re-pair before it syncs. Tech support's response? "Keep trying."