I shouldn’t need to point this out. It has been years and you still haven’t fixed the biggest problem in the game. Why has this not been sorted out yet?
What SHOULD happen: Game saves to File 1. Next time it saves to File 2. Then back to File 1 the time after that. If a file gets corrupted you can go back to the previous one and it will work fine.
What actually happens: Game saves to File 1 (savegame) and File 2 (savegame.bac) simultaneously and corrupts both simultaneously when it crashes, destroying all your save data unless you backed it up manually.
Bonus stupidity: The Steam Cloud will upload the corrupted/deleted save file and overwrite the otherwise perfectly good save data on the cloud if you open up the game and close it again after the corruption happens. And you probably will since you only know the save is corrupted when you open up the game again.
For the love of god, implement something to stop this happening. This is ridiculous. Why don’t you just make it so that as I suggested, it writes to two files alternating which it uses each time?
And/or make it so that the savegame.bac file is NEVER accessed at the same time as the savegame file. What’s the point in having a backup when it ALWAYS gets corrupted along with the file it is meant to be backing up?