The write-protection switch allows the user to lock an SD memory card so that no data can be written to, modified on or removed from the card. This is very useful for protecting important files. However, it's possible to forget that the write-protection switch is on. Fortunately, removing write protection is quick and simple.
Hold the SD card with the front facing you and the diagonally cut corner at the top right.
Locate the write-protection switch near the top of the left hand side of the card.
Slide the switch up, to the "unlock" position. If the switch was already in the "unlock" position, slide it down and up three times. Leave the card locked for 30 seconds, slide the switch up and try again.