My droid 2 came with a 16gb Sandisk micro SD card HC, class 4. Whenever i plug it into the phone it says unavailable or unmounted.. I took the card out and put it back in and still did not work. I tried a few other micro sd cards and none of them seemed to pop up on the phone. I reformatted the sd card twice and reset the phone. Still nothing. I called verizon and they did all the stuff they could help with but stuff i had already done. Whenever i plug the phone in the computer the sd card does not pop up. If i put the card itself in a micro sd card reader and put the card in that way and the computer read it just fine. I am not able to listen to music or able to take pictures at the moment. Any suggestions?