Hi Carbon_Shriek, Apple made some chanages in El Capitan that broke MoI v2 and v3.0 but there is a version 3.1 update available now for v3 which fixes that.

To get the version 3.1 update, put in your v3 license key here: http://moi3d.com/reinstall.htm , that should get you running on El Capitan.

- Michael