Hi all.

If you go to [MoI installation folder]\ui\customui\mods and edit ObjLibrary.cfg you'll be able to type in new path.

Format:

[NAME that will appear in the UI for that library][COMMA or SEMICOLON][PATH in quotes]

Example from my ObjLibrary.cfg:

Object Library;"D:\OneDrive\nurbs\objlib"



Also you can have multiple object libraries. And they will be separated by line in UI. I believe for new entry you also need to separate it with comma or semicolon.
All above is true for MoI v3.

And yes, you have to edit ObjLibrary.cfg with administrator privileges. So in win search you type 'notepad' (or any other text-editor of your choice). Click on it with right mouse button. Choose 'Run as Administrator'. Then in notepad you open ObjLibrary.cfg, edit it and save it.