I just got my a forerunner 645 music after using the forerunner 35 for 2 years. I love all the additional features of the 645, and for the first few days, it was working like a charm. Then today, my start-stop button stops working out of the blue. I think that it is a mechanical issue, and I decide that I should look up fixes. I see the one about soaking it in warm water for 10 minutes, button before I can do that, my watch buzzes uncontrollably. I look and see that my watch has started a run and paused it all on its own.
I figured out that the button has about a 20-minute lag, and I can't figure out how to fix it. I've tried resetting it using the backlight button, but that only turns the screen off because as soon as I turn it back on, I'm still in the run. I'm currently trying to run the battery out, but if anyone has any fixes that would be nice. If I can't figure it out soon, I might return it to amazon and try to get a new one.