When you make a search of duplicate items and move it, it is possible you will leave empty folders.
You can select the "Clone List to Scan" item from the "Control"menu (if it is enabled) or load a directory. You can then search for the empty folders with the same name, date modified and date created. The other filters will be ingnored and disabled. Choose "Empty folders" from the "Scan for..." button.
The window "Empty folders option" will appear and you can decide if you want to view only the empty folders that don't have the custom icon or both.
Note: the custom icon is an invisible file that is inside a folder and if you have many of these icons you probably have more empty folders.
Once you have the list of the empty folders you can use the "Mark/select Options" window to search inside the list of found folders.