I believe you can only Unlink at the level in which you published the Universe which I am assuming would be the group level. Try going to the group level in which the Universe was “exported to” and see if the option is available.
We rarely ever use the GENERAL SUPERVISOR account. The only time I know of is when we need to reset the logging back to the database for those occassions where it “forgets” and logs back to file.
As I think about it, I guess it won’t be a problem unlinking from the root group. I need to remove links to universes that were erroneously exported to multiple groups. Once I unlink, I’ll just have to export to the correct group. Another step in the process but nothing too onerous.