Copied from emails from my brother:
Yeah, try putting it in a computer first, then chkdsk (if Windows) or Disk Utility -> Verify Disk/Repair Disk (if Mac) but if that doesn’t work it’s gone, have to reformat. And back up/offload new photos right away, never trust anything your phone or computer to last as long as you think. 🙂
Looking at the link you posted again, it’s worth trying the drive letter thing and the recovery software linked by SanDisk as well.
The simple answer for drive corruption is “sometimes electronics mess up”. Electronic devices are a complex systems and anything complex has ways it will fail that are unpredictable and not easy to determine the cause… could be a defective card, bad connections, software glitch in the phone, etc.
Also, vocoder > autotune.