Debug mode is very useful to help locate the source of any problems when the LFNRENEW batch file has trouble renaming files. This typically occurs when files no longer exist or are currently in use.
When debug mode is enabled, LFNit! adds extra information to the LFNRENEW batch file to display the current filename being renamed. The DOS Shell typically does not display the filename when it renames files - this is where this option comes into its own.