The game keeps a lot of backups in %localappdata%\u01\Saved\SaveBackup\<steam id>\<profile id>\

There are 2 ways to use these backups:
A-delete GameSaveData.sav in %localappdata%\u01\Saved\SaveGames\<steam id>\<profile id>\ and the game should automatically load the latest backup.
B-take the most recent file in SaveBackup\..., rename it GameSaveData.sav, and replace the one in SaveGames\<steam id>\<profile id>\ .

Either way make sure Steam could is disabled before trying to revert saves.
Other possible sources of save issues: multiple steam accounts+family sharing (saves are tied to steam id), switching to old steam clients (some fail to supply correct steam id), logging as a different Windows users (because saves are in %localappdata% aka c:\Users\<your user name>\Appdata\local )


...Aannnd anticipating stanley's reply, on some computers, the 2 methods above can fail for unknown reasons, in which case the game refuses to load any backup, even manual ones, and we still don't know how the game can tell the most recent save from a copy-paste of a save it made 1h ago.

Thank you

I don't know why, but the Steam ID folder(?) where the folder is saved has changed. (My PC and Steam account haven't changed.)

I tried making new save data, and a different folder was created from the old data.

I copied the old data into that folder, and the save data was displayed, but I couldn't load it.

Is there any way to somehow revert the Steam ID folder link to the previous one?

If that's possible, maybe I'll be able to load it?

Just to be sure: it's the steam id (folder name) that changed, meaning that you have exactly 2 subfolders in %localappdata%\u01\Saved\SaveGames\, along with a file named EnhancedInputUserSettings.sav, is that right?
If I understand correctly, one of these folders should be "76561198020757237", what is the other?

Steam says "Your SteamID [...] can not be changed, even by Steam Support staff members." so it would be best to figure out why the game thinks your has changed, but if you can't, it is also possible to hex-edit saves to transfer them to a new Steam account.

In %localappdata%\u01\Saved\SaveGames\, there are three folders: 76561198020757237, 76561198020757237Pioneer, and KUBO-0 (a newly generated folder), as well as EnhancedInputUserSettings.sav.

Ok, "KUBO-0" is the one that shouldn't exist. The game creates a "computer name-0" folder when it fails getting the steam ID from steam.
For me, this happens when I try to run the game from an old version of the steam client (In my case the 2022 one, that still had the --no-browser option...).

So 2 options: run the game from a recent version of the client, or modify the game's exe to make it compatible with old steam.

I see.
If you had to choose between those two options, which would you choose?

And what operations should you perform?

Originally posted by Insane Chainsaw:

Originally posted by 元怒:

If you had to choose between those two options, which would you choose?

Depends if you want to keep the warranty seal / aren't into fiddling with softwares.
Option A is the safest, option B is for power users that don't like modern steam clients.
Personally, I went with option B.

Originally posted by 元怒:

And what operations should you perform?

Replacing the text "SteamUser023" by "SteamUser021" in U01-Win64-Shipping.exe using an hex editor, cheat engine, or notepad++ (NOT the notepad that comes with windows). Seems to be that simple for this game, but obviously you forfeit your right to file a bug report if something goes wrong.

Method A of updating my Steam client worked for me!
I'm very grateful to you! Thank you!!!

どういたしまして。