I just pulled my phone from my pocket and it was frozen so I pulled battery and restarted it. The SD card format was unrecognized. I stuck it in a card reader and it wouldn't show up on my pc. I stuck a different card in my phone and it is fine. I called Sprint and the card is not covered by warranty. The warranties are device specific and Samsung does not feel that they need to cover them. I was lucky that the Sprint store did replace my card with a Sandisk card. I have numerous Microsd cards. They all came with a lifetime warranty. Samsung fails on this note. I still love this phone, though. 
