In the first screenshot above, the volume MacPro HD is selected as a search location in the List To Scan (as indicated by the check-mark in its selection box). Clicking the triangle beside the hard drive icon expands the location, displaying the items or subcategories contained within, including the System folder. Clicking the (x) beside any folder excludes it from the search. In addition, the System folder and all associated items can be easily excluded by checking the Exclude the System folder and its associated items from the scan check button (the option is available only if the disk contains a System folder).

Looking at the middle screen capture, you can see that by clicking (x), the Test folder has been removed from the location list. Also note, a triangle on the right of the MacPro HD icon. This triangle indicates an item from that location has been excluded.

Clicking the triangle shows the list of items excluded from the search of MacPro HD – currently, that list contains the System folder as well as the Test folder. Clicking Restore all would remove these folders from the excluded list and add them back to the List to Scan. Restore can be used to selectively add any excluded folders back to the List to Scan.