Hello, my problem is that I have researched the Covarex enrichment process and have already enriched uranium in the forge. But after the reboot, the recipe in the forge was gone.

Did you install any other mods that might have removed the recipe? There's nothing in this mod that can arbitrarily remove any recipe, Kovarex included.

Exotic Space Industries and mods from the recommended list

I've not played Exotic Space Industries, so I don't know it in detail.

I did a quick look at its code. It seems to put Kovarex enrichment into the computer age, whatever that is. If you're past that point in ESI, then it must be one of the other recommended mods removing or editing Kovarex.

Since ESI lists this mod as an optional dependency, and your issue isn't coming from this mod directly, I'm going to direct you over to their discord for help: https://discord.gg/DhPxNAJ3nt