I am new to the Fujifilm system and recently bought a used XT4. I switched my two Lexar 256gb 1667x xc2 from my Olympus to my XT4. After a few uses I got the message to switch the camera off to reset (not sure if that is the correct wording of the message). That worked out ok. This weekend I had taken hundreds of shots and changed lens near the end of the day and got the message again. I switched it on and off and took a few more shots. When I got home I only had the shots from after I changed lens.
I am confused if it is a sd card problem with compatibility or if it is a more serious problem with the camera. I did notice that when I deleted the photos from the card rather than format it I did not have this problem or maybe that was a coincidence. I would appreciate any wisdom on this, thanks.