I had a Droid x which came with a generic 16 GB class 4 SD card. When I upgraded to the RAZR, I just put my SD card in the Razr. The card is now full. So, I bought a generic 32 GB class 10 SD card. I had tons of problems getting my RAZR to recognize it. Had to format it on my computer several times. Mounted and unmounted several times in my phone and turned the phone off several times. Finally, the phone recognized it. I can play my music files just fine, but it has lots of issues when I try to transfer files with my files app. I am also having issues with pictures. Sometimes, the camera switches to internal memory. Sometimes, it takes a pic to the SD card, but it is just an empty file. Other times, it takes a pic then blocks out 75% of it. Pics are fine when camera is on internal memory, so it is clearly an SD card issue. Since the card I have used for 3 years is generic, I am guessing the issue is not that the card I bought is generic. I am guessing my phone has issues with a class 10 card. I am going to re-sell the card I bought (it works fine in my computer) and buy a new one. Please help me know what to buy!