My Fitbit sense was working fine during a typical day. I had gotten a phone call on my iPhone and my Sense indicated it OK. After the phone call was complete the Sense still indicated the answer/cancel menu. I hit cancel and everything crashed after that. Now when I try to reboot with the USB jack plugged in on charge I get a brief indication that there's a connection with my windows computer after the screen goes blank but then there's a disconnect and the boot screen comes back. I tried letting the battery run down completely and then doing a recharge to maybe let the CPU reset but I didn't have any luck. My guess is that this is strictly a software issue but I've had no luck getting the Sense to restart properly. Opening up the watch and disconnecting the battery was another idea that I had but that hasn't been attempted yet. I have the tools to open up the Fitbit Ionic and have changed the batteries a couple of times in the past but I hear that doing that with the Sense is harder. At this point I have nothing to loose because my Sense in bricked and I just bought a new Apple watch. I like trying to fix electronics stuff and wouldn't be afraid to give it a try.