Just a heads up for everyone using the new Nikon D500. There is apparently an issue with the SD card but an easy workaround. It is likely a power issue related to using the touchscreen LCD for playback of an image recorded on the SD card. I had this happen at the NANPA Regional on Friday in both use of RAW+JPEG Basic and in Playback and Delete of a RAW image with a Basic JPEG displayed next. In both cases it happened on playback immediately after the shot - not later. It's probably resolved with a firmware update by Nikon, but I could not rule out Lexar.
It was easily resolved by turning off the camera and reinserting the card. Using just the XQD card eliminated the problem for the rest of the weekend under all conditions. The camera is great - blazing fast, accurate AF, easy to handle, nice high ISO performance, and good handling of low ISO and colors.
Also note that it uses the new UHS-II SD cards which perform best with a UHS-II reader. The cards are VERY fast. Fast XQD cards are even faster - near shooting speed without using the buffer unless you have very long bursts or lots of short bursts.
This problem has been reported with both Lexar UHS-II cards - the 1000x and the 2000x. I have the 2000x card. It has been reported to not be an issue with the Sandisk 280 MB/s UHS-II card. All of these cards work fine in earlier cameras but the interface is UHS-I in those cameras. This is the first UHS-II camera from Nikon. Each company designs their own software and components for the card and how it works in devices. Apparently there is a difference between SanDisk and Lexar in their UHS-II designs, and it's causing a problem. Sandisk has had other problems - for example, the 280 MB/s card is very slow in the D7100 compared to the Lexar 1000x due to the way it operates in compatibility mode in that camera.