Factorio Forums

Booted the game to play today, and the game says this message:
Corrupt map: unknown quality prototype ID 9. File has likely been corrupted due to failing hardware.
Well, the game was actually correct. I ran memtest86 and it showed 106 errors. I figured that the memory was unstable because when I lowered the frequency to 3200 mhz ands ran the test again, it passed with no errors.
However, I am now left with this issue: my last manual save, along with the 3 autosaves are all corrupted. The last save I have is the ¨first trip¨ that is automatically generated, from 10 hours of gameplay ago.
Is there any way I can repair my save or should I just bite the bullet and lose my progress? Anyway, the file is attached.

That looks like a bitflip, one of items on a transport line (i was not checking which one) was corrupted as it had quality "9" saved. Happy new year.

Thank you very much, happy new year for you too!

If the only corruption is a Quality ID being bit-flipped (as in this case), you can solve the issue by installing the Infinite Quality Tiers mod (which makes all Quality IDs valid) and re-saving the game. Then Load the game without the Infinite Quality mod and it will "migrate" all of the Items/Entities with invalid Quality IDs away. I was able to fix your Save using this method (no Hex-editing required!)

Depending upon the type of Corruption encountered it is likely-possible that you will have unknown item prototypes as well. This can (theoretically) be resolved by adding in a lot of dummy items in a mod, but I have not tried it yet.

Good Luck!