Factorio Forums

Last night when I launched Factorio I recieved a message stating " Opening zip C:/User/(My name)/AppData/Roaming/Factorio/saves/8-8-25.zip failed I/O error" I now cannot open that original file without that message popping up but the autosaves from that world still work. I decided to just continue playing on the autosave file and everything was fine until while I was making some changes on Gleba I noticed that now all of the buildings placed had random qualities. I recently got into the quality mechanics and only had rare and uncommon buildings on my platforms and a few on the different planets. But now I have random epic and legendary buildings throughout my base. Is there any way that I can recover my old save or be able to revert my world to have the buildings it originally did?

This is a hardware or os problem.

Since the error happened during I/O operation, I suggest to check Windows Journal, System tab, for I/O errors. Filter for errors, and scroll until you find exact timeframe when it happened.
Also, analyse SMART attributes for your drive, and do SMART Long Test.