Here you can list files and folders that you always want to exclude when searching for duplicate files. During installation, the Windows folder and Program files folder on your computer are added to this list. Hidden folders are not searched by default in AcuteFinder, since they usually contain sensitive files or configuration options, that should be left intact.
Additionally, you might want to exclude some common program folders, like: C:\Program files, C:\I386, archive folders and the MS Office folder.
You can add a folder to the list by pressing the "Add folder" button and pick the folder you want. You can temporarily remove a folder by unchecking it, or remove it altogether by selecting it and pressing the "Remove" button.
The same applies to the list of files to exclude. It may contain entries with wildcards, as in inst*.exe. By default, common installation utilities and program components are listed, since they often exists in more than one program folder and must not be deleted for proper functioning of your computer.