Most of this is a copy and paste from a post I did on the Nexus forums. I am reposting it here to have the information in a central location. The following information is accurate as I see it and has been verified in MO
You may have noticed as you install mods that some of them have an assigned category and some do not. MO
provides a limited set of categories out of the box. You can fix this in MO
by creating the missing categories.
To configure new categories go to settings and click Configure Mod Categories button across the bottom of the general tab. You will get a new window with the existing categories listed, if you can’t see all of the information in this window stretch it by dragging the right or left edge out a bit.
You can do the following in this window:
Single click on a category to select it. The entire row will become highlighted. Double clicking on ID, Name, Nexus IDs and Parent ID will enable the edit box for each one.
To add a missing category, right click on any of the existing categories to get a little pop up that will let you add or remove a category. Click the Add entry. A new blank category will be created above the highlighted category. MO
will assign a new ID to the category with “new” as the name for it.
To add the missing Nexus category go to the Nexus main page and click on the files button then select categories to open the categories page. To get nexus IDs hover your mouse over one of the categories and somewhere in your browser you should see the link preview. At the end of the link you will see CAT=some number. Example CAT=67 for Abobes - Player Homes.
Go back to MO
and highlight your new category. Double click on the “Nexus IDs” field and enter the number you got in the previous step. Double click on the name field to rename from “new” to the category you want to use.
You may have noticed that some categories have nested sub-categories. You can do this from the same dialog as above.
To nest a category you have to specify its Parent ID, the last column to the right of the window. For example you create a new category FOOD and MO
assigns a number to it (the ID), say 25. Create another category and call it ROTTEN. Edit the Parent ID in ROTTEN to 25. ROTTEN will now be a sub-category of FOOD.
If at any time you want to remove a category, highlight it, right click and select remove.
After you are satisfied with your edits close down MO
and navigate to the MO
folder and look for a file named “categories.dat”. Make a copy of this file and keep it in a safe place. If you ever need to re-install MO
copy it back to the main folder and your edits will ready to go.