How common of a problem is this? No apps on sd card, card never removed from phone, suddenly out of nowhere sd is showing as blank/corrupted file. Couldn't format.... nothing. Lost 300+ pictures. VZW didn't have any 16gb cards in stock so they're shipping one to me. In the meantime, they "loaned" a 16gb card to me from what they said was a new DX. Riiight. Anyway- what causes this and how common is it?