[2.1.15] Steam Achievements not unlocking despite earning in-game achievement

[threefold]

I have been playing (over 250 hours) on experimental 2.1 versions. A few days ago I received the achievement for visiting Aquilo for the first time on version 2.1.14 as normal. I've had three or four achievements in this playthrough just fine until today.

I got research with the Cryogenic Science pack for the first time, which unlocked the achievement and gave me the notification in game, but didn't unlock the Steam achievement, despite being signed in, up to date and online.

I have a suspicion this is because I unlocked this science pack achievement on version 2.1.15 (released in the afternoon of the 24/08) which has now been unlisted from Steam. It is no longer available for download due to the release of 2.1.16. I believe what happened is I earned the achievement in this 2.1.15 which is not on Steam and therefore didn't count towards my accounts progress of the Factorio achievements.

As far as I know there isn't any way (without deleting all achievements) to reset the in game achievements and have them resync with steam? I have no mods installed and everything else apart from the version difference is exactly the same as when I unlocked the previous Aquilo achievement just a few days ago. I've been playing Factorio since 2017 and have been working on the achievements since then. Does this now mean I'm permanently unable to get this Steam achievement?

Unlocked in Factorio. Locked on Steam. No Mods installed.

Screenshot 2026-08-24 221957.png (94.13 KiB) Viewed 227 times

[Rseding91]

Can you please provide the save file?

[threefold]

Most recent manual save just before the achievement for the research unlocked.

[Rseding91]

It looks like it failed to attach. Maybe you could send it through something like google drive, one-drive, dropbox?

[threefold]

It looks like it failed to attach. Maybe you could send it through something like google drive, one-drive, dropbox?

https://drive.google.com/file/d/1iJ-4nl ... drive_link

[Rockets]

I also just had this happen in 2.1.16 during my current run, without playing on 2.1.15 at all. I'm playing multiplayer with a friend to help him finish up achievements he's still missing, and he unlocked Lazy Bastard ingame just now without getting the steam achievement. I can send our saves if Threefold's aren't enough to reproduce it, but mostly I just wanted to let you know that 2.1.15 didn't cause it for us.

[Rseding91]

As far as I know achievements logic hasn’t changed since pre-2.0 (several years ago). So I have no idea what to do next with this.