Running outside using GPS, the watch is marking the laps correctly (lap distance is a mile) but the total mileage displayed during the run and recorded afterwards is off. I wait for the GPS to detect, click "Start" and as soon as I start moving it shows ~4.5 miles. Each lap will restart at that ~4.5 mile mark. I've sometimes been able to avoid this by clearing totals/history off the watch, but that seems like a kludge and it doesn't always work.