DiskLens › Duplicate file finder for Mac
Duplicate File Finder for Mac
Every "IMG_4417 (1).MOV", every "mix_final_FINAL.wav" — duplicates are the most deletable gigabytes on any disk. Drop a folder below and DiskLens groups the candidates instantly, entirely on your machine.
…or drag & drop a folder. 100% local — nothing uploads.
Where the space went
Top 50 largest files
Duplicate candidates
How DiskLens finds duplicates
DiskLens uses the strongest cheap signals first: files with the same name and the same byte size are, in practice, copies — either re-downloaded, re-saved by an app, or manually duplicated ("Grand Canyon.mov" and "Grand Canyon copy.mov" both show up because the name-normalized size group matches). Groups are ranked by wasted bytes: the total size of every copy beyond the first, so a 3-copy 4 GB video ranks above a hundred duplicate screenshots.
Native apps like Gemini 2 and Nektony go further with full content hashing and fuzzy photo matching — great if you have 30,000 near-duplicate photos. For everything else (Downloads, Movies, Documents, project folders), name+size grouping catches 90% of the waste with zero risk and zero cost.
How to clean duplicates safely
- Scan the right folder. Don't scan your whole disk — duplicates live where you save things: Downloads, Desktop, Movies, Pictures.
- Review each group. Check paths: keep the copy in your organized location, stage the strays in Downloads/Desktop.
- Verify before deleting. Open one file from the group. If it plays/loads, the siblings are safe to stage.
- Export a reviewed script (cleanup.sh) or delete directly in Chrome/Edge/Brave — both behind explicit confirmation, because browser deletion is permanent.
Free vs paid duplicate finders for Mac
| Tool | Price | Installs? | Uploads files? | Best for |
|---|---|---|---|---|
| DiskLens | Free | No — browser | Never | Fast name+size dupes in Downloads/Movies/projects |
| dupeGuru | Free (open source) | Yes | No | Full content-hash duplicates, cross-folder |
| Gemini 2 (MacPaw) | $19.99/yr subscription | Yes | No | Photos: near-duplicate & similar-image matching |
| Disk Drill | From $89 | Yes | No | Data recovery first, duplicates second |
Frequently asked questions
What is the best free duplicate file finder for Mac?
dupeGuru (open source, content hashing) and DiskLens (browser, name+size grouping) are both genuinely free. Paid apps add fuzzy photo matching.
Why same name AND same size?
Two files with different sizes cannot be identical, so size is the first filter. Adding the name filters re-downloads and re-saves cleanly. Content hashing every file would read every byte — slow for video folders.
Does deleting duplicates free real space?
Yes — duplicated video projects commonly waste 5–30 GB. Groups are ranked by wasted bytes so you reclaim the most space first.
Can it find duplicates in Photos library?
Leave the Photos library to Photos.app (it manages its own database). Scan exported folders and Downloads instead.
Why not hash every file like desktop apps do?
Content hashing reads every byte of every file — for a 3 GB video folder that means reading 3 GB from disk. Name + size grouping skips that entirely, which is how a browser tab can out-analyze a native app on large media folders. When two files share a name and exact byte count, they are copies in all but signature.