I ended up with corrupted files and a bad drive when I tried to use an SSD that was too slow. I wrote some software to try to get the footage back, and it worked until my computer had a crash at the same time I was transferring, which shot the whole drive.
Anyway, I present the software for you to consider at your own risk:
https://github.com/stephenplusplus/dropped-frames -- I intend to wrap it up in an installer, so it's just "download, install, & run!" but in its current state, it requires a few more commands.
I haven't tested on Windows, only on OS X. You will have to install Node.js first:
https://nodejs.org/en/download/ then in the Terminal application, run the commands you see here:
https://github.com/stephenplusplus/dropped-framesSorry for the complicated steps, but if anyone out there is in a desperate situation, I figured you might at least consider it. If you have any questions about it, let me know.