I have a been using a 64Gb card with no issues for 4 months, But now i have been having some problems with the gallery app. I only have 500 pictures in the card and gallery app is extremely slow, opening a pictures can take up to 2 minutes, and crashes all the time!! I tried to format the Sd card, factory reset the phone, upgraded to 4.3, downgraded to ICs and now i am running android jelly bean again. I downloaded a gallery app from the google play and it works without any problem. Does someone knows why the stock app is not working?