jims203 wrote:
For the most part it is best to use certain cards with specific cameras. Different model within the same brand use different versions of operating systems. I learned early on taking a card out of one without formatting it in the camera it is now being used in can render files not seen or inaccessible. Once the card works fine try just using it with that camera and see how that works.
The issue you are referring to is that when you you put the card in a different camera it creates a new folder. If your camera doesn't allow you to see both folders, you will find them when you put the card in a computer. With Nikon you can find the additional folders through the menu. I would guess that is the same for other brands.