I assume you are using SD cards purchased from a know good source.
Ebay contains lots of counterfeit memory cards.
Something to try:
If you have a card reader/writer on your computer:
Put the SD card in the card reader and delete every file and folder you find on the card.
Then put the SD card in your camera and use the Camera's Format command to format the card.
That usually works for troublesome cards.
If that does not work, I suggest you go to our Samsung Forum and post your question there.
That forum has moderators that work for Samsung.
Here is a link;
I have purchased numerous 2gb SD memory cards and my Samsung SC-10MMS
camera will not format the card. It gives me a message " not supported format". I have an older SanDsk 2gb SD card that works ok in the camera. Is there a new technology on these new cards that the camera will not support. Camera manufactured in 2006.