ACCEPTED FileAccess Interface for Skyrim Script - FISS (by Lord Conti)

[Kelmych]

Fiss doesn't need specific installation instructions since it should be installed by Mod Organizer in the ordinary way. Instructions on Nexus pages are often aimed at users who are not using a mod manager. You should remove the files that were added by manual installation and then install it with Mod Organizer.

[Chillaxulating]

Fiss doesn't need specific installation instructions since it should be installed by Mod Organizer in the ordinary way. Instructions on Nexus pages are often aimed at users who are not using a mod manager. You should remove the files that were added by manual installation and then install it with Mod Organizer.

Thank you. I tend to overthink and over complicate instructions. 

[Shadriss]

Unless specifically stated otherwise, ALL mods listed in the Guide are installed through MO. This includes FISS. The reason it is showing up as an unmanaged mod is because you have installed it into the actual SKyrim Data folders, which MO does not do. I would advise you to delete those files (check in the archive to see which ones they were and be certain), then install them through MO as you would any other mod.