Going to revive to follow up the DiskDrill recommendation! It's an under-rated tool that you'll hopefully never need. I recently had a clip get corrupted out of a Sony Venice and since AXSM media doesn't allow write-access to anything other than the Venice, the clip was stuck on the mag. Mac kept giving me errors and refused to copy the clip using Silverstack, Finder, Shotput and Hedge. Disk-Drill was something I found and it had no problems recovering the clip and was able to get it properly verified.
Took almost 2 days of sifting through the troubleshooting before I stumbled on Disk-Drill.
