TL;DR; I unfucked a micro sd used by a nintendo switch with one command: fsck

I had noticed that the nintendo switch displayed way more storage usage then it should. I didn't mind at first, but at some point I couldn't download any games. When I checked I saw some ridiculous storage usage.

According to the system, all games summed up ~20Gb, but >100Gb was in use? Sounds retarded, so I did the following:
* Plugged it into laptop
* Spend one our searching for a way to to access this seemingly unknown filesystem
* Find out this filesystem is actually exFAT
* Find out that 2/3 sd adapters suck
* check filesystem with dust (A visually more pleasing version of du)
* Find 20Gb of files, nothing hidden or whatever
* run fsck
* "File system contains some errors want me to fix then?"
* "Sure"
* check usage
* 17%

As for the reason why this happened in the first place, my guess is that the switch labels the whole segment of the card as used before downloading a game and it something goes wrong, it shits itself.

Anyways, fsck is a pretty useful command.