I've just recently updated to the 1.2.6 version of this mod, after there were a few minor issues I thought it might resolve. It has, in fact, created a variety of new ones. I'm playing in 1.10.2, and I'm using the Mekanism mod, and most of the problems have originated with the compatibility. I haven't touched Mekanism, so I'm assuming the problem is here.

So my first problem, is that when I came into the world, All of my tin and copper ore had disappeared. I'd already processed most into Mekanism ingots, so it wasn't a huge loss, but I know that amount of ingots isn't going to last me the whole world length. I've added them to the /config/ExNihiloOmnia/registries/ore/whitelist.txt file. They work, but only as Ex Nihilo Omnia ingots.

My second, and more relevant problem, is that it doesn't seem to want to read the config file. I've edited it to suit my preferences, like using the Mekanism Enrichment Chamber as if it were an OreDict ore, and it worked in previous versions. It's just now that it doesn't. I'm guessing that it's a problem with the config file,

I've reset the config file but it still isn't working, I'm gonna have to revert a few versions to see if I can get it working how I liked it, but I'm just going to bring this to your attention. Hopefully it's enough information.

(I'm using Forge 1.10.2 12.18.3.2234 if that's needed information.)

A quick update. I've reverted back to Ex Nihilo Omnia 1.1.4, since that was the last one it worked on I believe.