Hi there
Are you automatically creating the TOC? Even if you were,
unless there is a topic inside the folder I'd be totally surprised
if it was listed there.
The bottom line is that RoboHelp believes there is content
inside the folder that is still being used. This means you have a
reference somewhere inside a topic pointing to something inside the
folder. Might be an image, CSS file or something else.
Once you figure out what that something is, you are able to
kill the reference and finally delete the folder from RoboHelp.
Cheers... Rick