Similar in form and function to the Search Paths docking window pane, the Exclusions pane allows you to indicate which file system paths should be excluded from duplicate file search operations.
Note that, like the search paths, a default set of excluded paths is provided for you when a new project is created. This behavior can be altered in the preferences window if desired. Generally speaking, it is recommended that you exclude file system paths that may contain sensitive files such as those used by the Windows operating system or third-party software. This can also dramatically reduce the working file set and produce faster duplicate file search results.
Please review the Search Paths section of this help file for usage details.