When this option is checked, Duplicate Cleaner will not allow you to remove files from system folders such a Program Files and Windows. In addition, the system folders will automatically be excluded from the scan.
When checked, Duplicate Cleaner will automatically remove a group when there is only one member left.
After a file removal operation, removed files are dropped from the main duplicate files list. When this option is checked, groups consisting of 1 file will also be dropped from the list (i.e. The remaining file is no longer a duplicate).