So scary… I have 2 batteries , never had a problem with any of them. I flew with one,100% full, and after flying for a minute or two I got the "invalid battery" message for the first time ever, then it came back home safely. I switched to the other battery, no problems and 99% full, started flying. Took 2 photos.. by the time it finished recording the second photo, it simply shut down and fell, propellers first, thankfully on the grass and did not hurt anyone or damage anything. The drone looks fine and starts normally, I just didn't try flying again. I have no idea what happened. The app froze when it lost connection, it was not too high (maybe 40 feet high) and just hovering still because I was composing a photo of people on the ground. Also no wind at all. I am really concerned about flying it again - I wrote DJI but it's Christmas day and I don't think they had a chance to get my message yet. I would love to hear your opinions .