Duplicate File Finder

The Duplicate File Finder finds exact duplicate files within a chosen folder.

Why Use It

Duplicate files waste disk space silently. The finder locates them with certainty — only files that hash identically are reported as duplicates.

How It Works

A staged pipeline avoids hashing every file in full:

1. Collect files — walk the folder, skip excluded directories and extensions
2. Size filtering — group files by byte size; only groups with 2+ files proceed (files under 50 KB are skipped)
3. Header hash — hash the first 4 KB (SHA-256) of each candidate
4. Full hash — stream the full content (SHA-256, 64 KB chunks) to confirm exact matches

Hashing runs in Swift actors for race-free parallelism.

Scan Exclusions

System directories, the Library folder, VCS folders (.git, .svn), build artifacts (DerivedData, node_modules, Pods, .build), caches, and app bundles are never scanned. Source code, fonts, databases, and localization files are excluded from results — they are never suggested for deletion.

Smart Selection

After a scan, one strategy is applied to each group:

Strategy	Keeps
Keep Oldest (default)	The oldest file by modification date
Keep Newest	The newest file by modification date
Select All	Every copy
Deselect All	Nothing

You can always override the selection per file before deleting.

Deleting

Selected files are moved to Trash via trashItem(at:) — recoverable by default. Only files inside the scanned folder and outside protected system paths are processed.

Search

The search field filters groups by file name or path.