Factorio Forums

When you get vanilla achievements from a modded save, it won't give you Steam achievements.

But, if you delete all of your mods, toggling them off doesn't work, the game awards you the Steam achievements you would have gotten.

that is one of the flaws the achievement system has but is stated that it wont be fixed since there are always ways to get the achievements
viewtopic.php?f=58&t=28608

Wont fix