SC cards have caused me several problems due to the slider on the side which activates the write protect feature. Usually one or more of your cards will develop the habit of sliding to write protect mode when you insert them into the camera. When this happens I can correct the problem filing it down a little. The cards will usually work if you completely remove the offending useless slider. Now I have a San Disc card,which I have been told is the best brand available in which the lever has disappeared but the card now shows a permanent message: "write protected " when inserted into any camera. I will have to discard this card. I have two questions. 1.) why do SC cards have a "write protected slider? Any camera I have ever owned will warn you that the card is full and will not take a pictures on a full card. I would prefer cards without this slider which has caused me frequent problems,though I have never had one completely disappear. I am mostly using an OLY M-5 Mkll,which has always felt a little rough when inserting a card. I am not the only one who has observed this roughness. 2.) Has anyone else had a similar problem or has a solution? Based on some past comments on the subject of cards and card slots, yes I put the cards in carefully and no I don't put them in backwards.