With terabyte disks, duplicate files are a matter of convenience, not capacity. Today's tools actually do a great job at what earlier programs failed to do: distinguish actual duplicate files by more than name or size. NoDupe from OTIS Soft compares the actual content of files, not just their attributes or metadata. This free tool's specialty is finding duplicate music files.
NoDupe's user interface is very plain but super-easy to understand: Tabs for Search and Results in the main window, and one entry, a Help file (which also accesses the log), in the menu bar. To the left of the main view, a drop-down list offered search types: All Files, Directories, Large Files, and Music Files. We could add custom searches, too; a Customize Search pop-up let us enter specific extensions to search, filter by file size, and set other options. We set our search type, Music Files, and selected two physical disks to search in the Search tab's tree view, though we could browse to any folder or directory to further narrow and speed up our search. NoDupe tracked its progress as it compared large numbers of files. When it finished its scan, NoDupe presented its findings in numbered, highlighted groups in the Results tab. Check boxes let us select files to export, which moves files to a new directory and saves them as a CSV file. A handy Auto Mark tool automatically selects batches of files by date, size, or path, based on cutoff points we entered in the settings. The Preview tool is especially valuable for sorting out duplicate pictures. When it's selected, it displays a small preview (or large thumbnail) of images and other compatible files in a pop-up. When we we'd made our choices, we pressed Delete to remove all the checked duplicates at once.
NoDupe proved capable at distinguishing duplicates from versions and completely different files that look like duplicates. We'd like to see Select All and Deselect All buttons (especially Deselect All) since it's possible to overlook checked files in long file lists. Beyond that, it's hard to fault NoDupe, which can sort out your far-flung music archives.