Rise of the Ronin developers are investigating a lost save data issue
If you have noticed save issues with your Steam playthrough of Rise of the Ronin, you are not alone. Players have been making their issues known via the Steam community page. Thanks to VideoGamesChronicle for originally noticing these messages. A few players report losing a few hours of progress, while one unfortunate player has apparently lost between ten and fifteen hours of gameplay. Personally, I don’t blame someone for never returning to the game again after that.