so i downloaded the latest jar you just released and i got this when i loaded into my world from crafttweaker.
[POSTINITIALIZATION][CLIENT][ERROR] system: manufactory is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: isotope_separator is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: decay_hastener is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: fuel_reprocessor is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: alloy_furnace is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: infuser is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: melter is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: supercooler is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: electrolyser is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: irradiator is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: ingot_former is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: pressurizer is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: chemical_reactor is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: salt_mixer is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: crystallizer is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: dissolver is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: fission is already defined in that package
[POSTINITIALIZATION][CLIENT][ERROR] system: fusion is already defined in that package

@turbodiesel4598
Seems like CraftTweaker handlers registered twice.

@turbodiesel4598 no it didn't crash the game, thank goodness as i haven't changed any recipes yet. All you get is that error showing ingame and i figured you should know about it.
it does get a bit annoying though . . .

So i just downloaded the updated 2.8 jar and still getting the same error

That is very strange, as I didn’t change any CraftTweaker integration code with this update, but I’ll look into it - does this error crash the game?

@turbodiesel4598
Try to remove annotation ZenRegister from all classes, which manually registered as handlers for CraftTweaker.
Reason: https://github.com/jaredlll08/CraftTweaker/blob/1.12/CraftTweaker2-API/src/main/java/crafttweaker/annotations/ZenRegister.java#L5-L8

Yeh, I didn't fix the bug in that release - that was a hotfix for a crash that was occurring with reactor ports.

Ah, ok, I think I found the issue - it's only appeared as of the latest CraftTweaker update. Will get a fix out when I can :)

Actually, the issue is that you are registering your handlers twice, you are using ZenRegister, and then manually registering here (too late to be called in a sciprt may I add)
https://github.com/turbodiesel4598/NuclearCraft/blob/master/src/main/java/nc/integration/crafttweaker/NCCraftTweaker.java#L16-L35

Cheers @jaredlll08 , sorted it. It's only recently that the message has appeared in chat though right? Because that mistake's been there for some time :P

Fixed in version 2.8b :)

thank you so much!

No prob!