Hi Dropbox and forum,
There seems to be no way of removing all access of an external user to files/folders shared to him.
Lets say you have a team folder with "Projects", and in this folder you have hundreds of subfolders shared with different external collaborators. One user has been invited to 70 of the subfolders, and you need to remove his access to everything.
As far as i see, there is no other way to remove this user but to go through every one of the 70 folders and manually remove him.
If this isn't possible, it should really be a high priority feature request.