Crashes on startup when using this mod in my custom modpack.
crash log: https://pastebin.com/DKSbrfYJ
I don't know if this is a compatibility issue with other mods.
But removing this mixin in immersiveindustry.mixins.json fixed it.

where was the mixin that you removed

where was the mixin that you removed
You need to remove in the client field: DatapackFailureScreenMixin.
It will look like in the second screenshot.
After that you will stop crashes.