On the Content Library tab, click the Context Menu button at the top and then select “Scan Known Directories for Files” and that will put them in the unassigned directory. If you have already imported their metadata, then there’s not an easy way to go backwards. Instead you should be able to go to Products > [ product name ] and custom categorize from there.
It was a good solution for a new problem: Categorize wasn’t working.
I didn’t use “Scan” because not all compressed poser types was viewed in “unassigned directory”, and I had been categorizing from “proser format” branch without problems. Suddenly, categorize didn’t work more, I only obtained empty subfolders categorizing files differents to *.crz (Yes, I check in subcategorie when i create it). Reading your answer remember me this option. I select it ... and categorize funtionality is back. Thanks.