I have on two separate occasions had the experience of making videos with GoPro Hero 8 on trips, coming back home, and putting the SD card into a computer to view the videos. The videos would view at first, but then for some reason, a problem occurred. I would get the message that the SD card needed to be re-formatted. I called the SansDisc company and talked with them about it. On both occasions they sent replacement cards to me, but that doesn't help with the lost videos. They had no explanation for why this might have happened. Now I've got another trip coming up. I'll take a different brand of SD cards this time and am planning to use several different cards so that hopefully at least some of them won't fail. But I have no idea what if anything I might have done or failed to do that caused this problem. Any ideas?