How to Find Duplicate Files on Mac (Photos, Videos, and Folders)
Duplicate files are one of the most frustrating sources of wasted space. You might import the same photo twice, download the same PDF from email, or copy a folder without realizing it already exists elsewhere.
This article explains what counts as a true duplicate on macOS, where to look first, and how NythyCleaner finds byte-for-byte identical files using a native SHA-256 workflow—with a review step before anything is removed.
Two Kinds of “Duplicate”
Exact duplicates (same bytes)
Two files are identical if they share the same size and the same cryptographic hash from a full read (or a verified byte-for-byte comparison). This is reliable for documents, ZIP files, installers, photos, and videos alike.
Similar-looking files (not grouped here)
Exports after resize, crop, or re-encoding can look like duplicates but are not the same bytes. NythyCleaner’s Duplicate Finder only groups exact matches—same full hash—so those variants stay separate until you handle them manually.
NythyCleaner’s Duplicate Finder walks the folders you choose, buckets candidates by size, and confirms matches with SHA-256 so identical copies appear in reviewable groups even when names or timestamps differ.
Where Duplicates Hide on macOS
High-yield folders to scan:
- Photos library exports — multiple exports of the same album.
- Downloads — repeated downloads of the same attachment.
- Desktop and Documents — drag-and-drop copies of the same files.
- External drives — backups copied onto the Mac without deduplication.
- Cloud sync folders — iCloud Drive or Dropbox with conflicted copies.
For a full disk overview before you delete anything, use the Disk Space treemap to see which folders dominate.
Manual Approaches (Limited)
- Finder: Sort by size and name in a single folder—works for obvious duplicates, not across drives.
- Terminal:
fdupesor similar tools can find exact duplicates by hash; NythyCleaner performs the same class of exact matching with an integrated UI and optimized native code.
Use NythyCleaner’s Duplicate Finder
- Choose volumes or folders you want to scan.
- Start a scan. The app groups files that share the same size and identical SHA-256 hash.
- Review groups before deletion—keep the path or version you want.
- Delete or move extras in bulk when you are confident.
Always keep backups of important libraries before large deletions.
How This Fits Your Cleanup Workflow
- Pair with freeing up disk space on Mac for caches and large files.
- If iCloud is tight, read iCloud Drive cleanup.
Summary
| Approach | What it finds |
|---|---|
| Same size + SHA-256 | Exact file copies (any type) |
| Different file bytes | Edited or re-encoded files—not grouped as duplicates |
Finding duplicates on Mac is straightforward when the tool matches the problem: NythyCleaner focuses on exact deduplication with a clear review step before anything is removed—ideal for Downloads, archives, synced folders, and project trees.