Originally posted by slartibartfast01 If you have a spare SD card lying around you could try formatting it on a PC then see if the Pentax folder is created when the card is inserted in the camera.
OK … done that … insert a PC-formatted card into the camera and the DCIM, PENTAX and PENTAX/K-3-III folders are created immediately, without switching the camera on. This'll be the flicker of the orange "Card Access Lamp" when the card is inserted
The FILES.DAT isn't created until a picture is taken … in this case, with the first lens to hand, a pre-set manual 28mm, the file is 88 bytes.
If anyone wants more detail than that they can create their own FILES.DAT files with different lenses and compare the contents thereof (which aren't in text or other recognisable format).
Enjoy