I've been following this thread as a Z9 owner. As others have said, we probably will never know what really happened. However, simple logic seems to say that it was not the camera, the cards, or the batteries but a failure of the software for an unknown reason. I've had this happen to me in the past, although not permanently. A friend and I were at the beach in Oregon, both using Nikons but different models and shooting near each other. All of a sudden my camera went dead. I took out the battery, replaced it, and turned the camera on and it was still dead. About that time my friend started walking toward me and said, as she neared, "can I use your second camera, my camera is dead." I told her my camera was also dead. None of the other photographers in the group were near our location and did not seem to be having any problem. We waited several minutes and then took the batteries out and put them back in and both cameras started up fine without any more issues. Obviously something in the air around or above us affected the cameras temporarily. I got my Z9 in March and have used it without any issues to shoot several times, including 19 days in Africa. What we are now using is a computer that happens to take photographs and it is susceptible to outside influences around us.