Odd behavior

ZinnaCookie​  It's worth searching your computer for the save, just to make sure there isn't a copy hiding somewhere.  Open a File Explorer window, click This PC in the left panel, and enter Slot_ in the search field in the upper-right corner.  The search may take a while to finish; when it's done, review the modified dates on the files it found to see whether your save is there.

You can also check onedrive.com if OneDrive has been active on your computer.  Even if you never use it, OneDrive could have synced your files in the background without your noticing.

As far as corrupt saves go, the files themselves are typically intact, just not readable by the game, or if they're readable, they can't be loaded properly.  The file itself shouldn't just vanish.