Factorio Forums

prerequisites = {"biter-egg-handling", "fusion-reactor"}, Are you playing with any Mods, perhaps one which removes Biter Eggs? (but does not change this Technology) It should still be Visible in the Tech tree on Vanilla... Or have you just not "Triggered" the Biter Egg technology, and it is somehow hiding?

im playing in peaceful mode... i have a bunch of mods.... only 1 around biter eggs. I removed it, but no difference. No idea whats going on. I cant see that portion of the tree at all. Captivity is the last thing on that tree for me....

It's going to be a mod. Only thing you can do is remove them one at a time and figure out which one is causing the problem (or which ones are causing the conflict).

Removing mods doesn't always undo the changes they've made to the tech tree iirc

computeraddict wrote: Fri Jun 20, 2025 7:37 pm Removing mods doesn't always undo the changes they've made to the tech tree iirc

Oh, good to know... That might really suck for this player.

what really sucks, is i have another save - with the same mods..... and this issue does not show there. I have already beaten that save..... no idea...

You can run /c game.player.force.reset_technology_effects() twice and see if it fixes it. You will no longer get achievements though if you save after running the command.

Thanks for the console command..... unfortunately no difference

Then this is not an issue with removed mods.

Chances are one of your mods has disabled the biter egg research without removing it as a prerequisite for promethium research, though it also could've been some other tech one of the mods added as well.


You can try hitting Ctrl+Shift+E to open the prototype explorer , selecting 'technology' in the left side dropdown, find the biter egg research in the left hand side (or use the search, probably faster), click the arrow, and look for the 'prototype-history' section. It'll tell you what mods have altered that technology - chances are its one of those that caused the issue. Often its caused by either a mod conflict or a bad mod setting.
In this image, I opened the rocket silo research and the prototype history shows two mods have altered it - base 2.0.55 (that's Factorio), and Asteroid_mining 2.0.11, which added some recipe effects to it.

You could also use the prototype explorer to look at the promethium tech and see what it lists under prerequisites - anything listed other than "fusion-reactor" is a problem.