I don't use KubeJS, never even heard of it.
But after doing what "Ugdhar" suggested earlier in this post with the "config/Mekanism/generator-storage.toml", I tried going into an individual save's serverconfig folder, and just deleting everything except the parcool folder (I have that mod installed.)

Then, a bit of loading and temporary freezing later, seems to have worked.
Even when quitting to menu and loading back in, or also when quitting to menu, exiting to desktop, and re-launching MC, choose a save and loading it.

And now to add salt to injury, I keep seing this message in game:

[Mekanism] Broken tags in Mekanism recipes detected, please check server logs for details.
You will be missing some recipes and machines may not accept expected inputs.

What does that mean and how can I fix that too ?

Okay, now for some reason it's another file causing issues.
Why does it seem to endlessly switch files ?

Here's another log, I don't get it:
https://paste.ee/p/K7P45mw8

10 minutes ago, Ugdhar said:

When you play Minecraft in single player there is still a server, it's just running on the same computer as the client, and not launched as a separate program, it's all done for you as the single player experience.

Try backing up, and then deleting, the config/Mekanism/generator-storage.toml and config/curios-server.toml files, it should recreate them correctly when you start the game again.

I tried doing just that and booting up a random world, but It still crashes with this exact same log.
https://paste.ee/p/oHSKrDI1

 

For the "curios-server.toml" file, is it normal that it's only in the serverconfig folder inside of my individual saves ?
Since that file is not present in the config folder.

Hey, first time being on this site since I've had crashes I can't figure out.
Keeps happening for seemingly no reason as earlier today I was playing MC just fine.

And before the logs were either fml.txt or client.text ... but now are server.text ?
(I'm only playing single player, never once used any server stuff or been on a server.)
Hopefully someone can make heads of this mess.. 🤕

Links to logs I got:

https://paste.ee/p/kn7W3q2l
https://paste.ee/p/15f47bG2