Sometimes I make pretty dumb mistakes.
I saved the game, made a couple more changes, and wanted to save the game again with saving previous backups.
I deleted the .db file, but did not rename the backup file. And pressed the save button.
After several errors I closed the game through the task manager. I checked the game folder the next day. Both backup save files were corrupted.
I tried to repeat it. I downloaded a new one .db file from the forum, saved the game a couple of times to create backups, deleted .db and clicked the save button. The game made an error and created a new one .db file. This file and the first backup file occupied 0 bytes of memory. The first backup was corrupted immediately at click the save button.
After closing the error window several times, I checked the game folder again. All 3 save files had a weight of 4 KB.
The game continued to give errors, so after a couple of minutes of holding the Enter key, I closed it through the task manager.
After trying to launch the game, I got 4 errors and an empty window. Clicking on any buttons caused several errors.
I suppose checking for a .db file in game folder and interrupt saving if there’s no .db could easily prevent this from happening.
Goodbye, my 205-year game. 