Oops. The little latch on the side in the unlock position, should engage a switch in the camera, indicating the memory card is not writ protected. It is not an electrical switch doing something in the memory card. But is the switch in the camera is defect, you get the same result. If someone once tried to press in a memory card, the wrong way around, this could have been the cause of a damaged switch. Just check the memory card slot, of nothing is in the cardholder, blocking the little switch from working correct. Sure the switch is in the up position, like in the picture?