I missed my opportunity to do the Hollow Knight ending because I had picked up the Void Soul, so I was looking to use an uploaded savegame to be able to beat him pre Void Soul and get the ending. Thing is, I used a save game that ended up being 100+% and it unlocked a bunch of achievements I didn't earn. I'm looking to wipe the achievements so I can load my legit save which will re-unlock the stuff I did myself, but I'm having trouble figuring out where the particular file that tracks that info is. Anybody know?

The last time I had this problem, they were sitting in the registry. You'll have to find a program called "regedit" on your pc, and find the Team Cherry folder or Hollow Knight folder, and delete it. This will most likely also remove your game settings, but saves should be ok as they are somewhere else.