It could be that there’s Autosave is having problems. But if that’s the case it can’t have deleted your old files… Can you try a manual save and see if the folder appears in your user location?
The game doesn’t need to be installed, you can just unzip it anywhere and it will always refer to the same folder. You could check if it[s not a problem on your end by starting a new game and clicking save on one of the slots manually. You can then check in your user folder, if TTSaves appears.
