In Duplicate File Detective, application Preferences are those not directly associated with the current project. Preferences are not saved and loaded as part of a project, and are in effect regardless of what project is currently loaded.
Saving and Loading Program Settings
Duplicate File Detective allows you to save program settings to the file system. Files produced this way can be re-loaded later or used by the command line interface or task scheduler.
To save program settings, click the drop-down arrow that appears below the Settings button in the main window ribbon bar and select "Save to File". Use the "Load from File" option to re-load them.