I have had the R5 and same Ascend CFexpress card for over a year. It worked fine. Over the last couple of weeks I have started to lose photos. I know they recorded, because I could view them on my camera and could scroll back through all of them. Multiple times, when I try to view them on my computer, they are lost. When I put the card back into the camera, they are gone. Earlier photos are still able to be seen, so not all photos are missing or deleted. What is going on?
Have you tried using a different CF Express card instead. Does the other card slot exhibit this problem too. Is the camera set to record to both cards simultaneously. If so are the missing pictures on that card.
Do you format the CF cards before first use in the camera.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.