We get into habits and one of them may well be when we get back from a shoot, of taking the media card out of the camera, be it a Compact Flash (CF), a Secure Digital (SD), or whatever and placing it into the reader slot in our PC's to ingest for saving or working on them. Then once they are in the PC we right-click on Format. Done, now we are ready to shoot again. But should we do it that way? OK this is not an example of format corruption but I thought I'd scare you anyway. I would not and I do not allow my PC to format my flash memory. A PC has it's own formatting procedure and it does so from the PC angle. To prevent this I never take the card out unless it is full and I need a fresh card for more shots. When I get to the ingesting of data into my PC, I will USB cable to PC. The camera is specific to the type of formatting it was engineered to do even given the media card format specifications. All Canon, Nikon, Pentax, Hasselblad, Mamiya and so on (with few exceptions)