This is a small text files to correct Mod Organizer blank/wrong category when you installed/download from Nexus Fallout 4 page.

DON'T USE THIS FILE if you use MO to manage other games than Fallout 4 (Skyrim for instance)
THIS files work as replacement.

Before you proceed, BACKUP your original categories.dat files first.

How to use :
Download the files manually (don't use NMM/MO obviously)
Extract/copy "categories.dat" files to your %appdata%/local/ModOrganizer/Fallout 4
Overwrite your existing categories.dat with the file you download.

By default, it will not changed the already installed mod categories.
It only affecting a new one.
So you must remove the "old" mod, then reinstall (just reinstalling will not work, you have to remove the mod first)

Note :
If it does changed the already category, that's because the default categories.dat use a wrong Nexus category id.
I didn't test this on already existing mod installation, i test this from scratch install (i delete the original categories.dat)

Remember, backup first before you try this file (it won't screw-up your mod /load order, but there's possibility it will change the category)