Factorio Forums

I read the instructions but I can't produce all requested attachments, as it happened few days ago, and only when I posted on reddit to warn others, I understood it is a Factorio bug and not a mod bug.

TL;DR: joining an online SE server was enough to break some of my blueprints, even without using them there. It happened to several players on the server, not all. My finding: game replaced electronic-circuit recipe with electronic-circuit-wood.

Expected: Mods and recipe changes shouldn't be able to modify your library blueprints.


I joined an online SE game for a while, then later went back to normal / SA. Just joining the server was enough. I did not need to actually use the blueprints there for them to get ruined. It also did not happen to everyone. Several players got it, some did not, and I still don't know why.

Symptoms were:

• assemblers set to "no recipe"
• blueprint marked as not editable
• message saying something like: "this blueprint cannot be altered, its data is saved separately to allow restoration of modded content"

The common thing in the damaged blueprints was that they had green circuits in them. Other parts of the same blueprint still looked fine.

Tried to fix - but when I exported from SA, SE-side data was missing and when I exported from SE, SA-side data was missing. Checked and found: game replaced electronic-circuit recipe with electronic-circuit-wood.

I wrote a script to merge the 2 books and posted it on reddit for others, and then I saw: 1. it happens to others. 2. Probably a Factorio bug


Versions:
- 2.0.76 - factorio space age
- SE: Server owner told me it was the current version, I have no way to validate

I can confirm an occurrence of this issue.

I loaded a Space Exploration save. When I subsequently returned to a Space Age configuration I noticed any of my blueprints seemingly showed no recipe where electronic-circuit should be. Syncing back with the SE save, loading it, and viewing my blueprints, they had the electronic-circuit-wood recipe.

there was such a bug in version 1.1.
viewtopic.php?t=104606
viewtopic.php?t=109128

the only solution: a separate copy of the game for each mod

It looks like the underlying reason is mod(s) changing recipe categories on assembling machines causing some recipes that were acceptable outside of the mods to be removed when loaded in the modded case. However, the 'blueprints changed when loading, keep old version for loading without mods' logic isn't detecting this case.

Actually it's 2 things: the above mentioned issue and mods adding explicit migrations. Migrations do not count for the blueprint library "the blueprint was changed due to mods, keep old version for when the mod is removed". The reason being: if it worked this way every update to mod(s) would trigger almost every blueprint to go into the "contents changed, revert mods to be able to edit".

There's no clear way to detect the difference between mods doing this on purpose due to mod updates and mods doing this because you joined a server and had blueprints from different mod sets that *shouldn't* be changed.

If it's too strict then mod updates will flag blueprints and lock them - making updating mods annoying. If it's too lose then you get the issue mentioned in this report.

The bug is very unpleasant because the game changes blueprints without warning the player and it is impossible to cancel it.
Broken blueprints may not be noticed immediately, but discovered after 6 months.

IMHO any changes to blueprints should only occur after confirmation by the player:
* the blueprint is marked with a "!"
* the player must understand what will be changed in the blueprint: recipe A will be replaced with recipe B, etc.
* the player can upgrade the blueprint, the "!" disappears
* the player can use the blueprint without upgrading, the "!" remains
* the player can upgrade the entire book of blueprints at once
* the player can upgrade his entire library at once
this will eliminate any surprises for the player

P.S. It might be worth considering a backup system for the blueprint library: beginning of the month, beginning of the week, yesterday

Rseding91 wrote: Wed Apr 01, 2026 4:19 pm There's no clear way to detect the difference between mods doing this on purpose due to mod updates and mods doing this because you joined a server and had blueprints from different mod sets that *shouldn't* be changed.

I don't know how it works behind the sense, but can't you identify "same mod id, newer version" and "different mod id, it is not the same configuration"?