+Luis Enrique Martínez Medina
unfortunately I didn't. It seems there is really no way to recover corrupted Wii u hard drive data (that I could find). It might be different if you can still boot the system and copy files, but I couldn't.
I'm pretty sure my drive was corrupted somehow, possibly by turning off the system while it was still trying to save or something. It's also possible that it happened because I'm using a drive with a Y-cable instead of the recommended drives with external power source. I eventually gave in and re formatted my hard drive and re downloaded all my DLC and games. My save files are forever lost.
Basically my lesson learned here was that if the game data is important, save it on the Wii U internal storage just to be safe. Honestly I've barely touched my Wii U since then because I don't want to replay everything. Really sucks. But I'm being really careful now and trying to make sure I power down the system properly just in case.
Sorry I couldn't be of help, I feel your pain :(