# Duplicate Finder — Find duplicate files and photos on Mac

Find identical files and look-alike photos, and clear the extras safely. Part of OneMacTools, 151 private tools in one native Mac app (macOS 26 or later); category: Files. Runs on your Mac; nothing is uploaded.

Finds exact duplicates by comparing file contents, and optionally photos that look the same even when resized or re-saved. See how much space you'd free, and move extra copies to the Trash (look-alikes are only ever reported).

Page: https://www.onemactools.com/tools/duplicate-finder · Download: https://www.onemactools.com/download · Pricing: https://www.onemactools.com/pricing

## How to use it
1. **Drop folders or files.** Drag in the folders to search, such as Pictures, Documents or an external drive. Sub-folders are searched too.
2. **Choose what to look for.** Exact duplicates are always found. Turn on Also find similar-looking photos to catch resized or re-saved copies too.
3. **Report or clean up.** Leave Then on Just show me a report to see what's there, or choose Move extra copies to the Trash and pick which copy to keep.
4. **Click Find.** Files are compared by their contents. When it's done you see how many extra copies there are and how much space they use.
5. **Read the report.** A “Duplicates report” spreadsheet (CSV) is saved in a new dated folder in Downloads › OneMacTools, listing every group, which copy is kept and where each file is. Open it with the Preview (eye) button.

## Options
- **Also find similar-looking photos:** Off by default. Also groups photos that look the same but aren't identical files, such as a resized copy or one re-saved as JPEG. Look-alikes are only ever listed in the report, never moved to the Trash.
- **Then:** Just show me a report (the default) or Move extra copies to the Trash. Moving keeps one copy of each set of identical files and moves the rest to the Trash, where you can put them back.
- **Keep:** Only shown when Then is Move extra copies to the Trash. The best copy (one outside Downloads, then the oldest), The oldest copy, The newest copy (by creation date) or The shortest name. The shortest name usually keeps “Photo.jpg” over “Photo copy 2.jpg”.

## Tips
- Run a report first and look through it before choosing Move extra copies to the Trash.
- The best copy suits most cases: a second copy in Downloads is usually the re-download, and the oldest elsewhere is usually the original in the right place.
- Look-alike photos are often edits or slightly different shots you might want to keep. Check them in the report and delete by hand.
- Empty the Trash only once you're sure. Until then, every moved copy can be put back with File › Put Back in Finder.
- The Photos library is skipped, because files inside it must be managed in Photos. Use the duplicates album in the Photos app for those.

## Questions
**How do I find duplicate files on a Mac?**
Drop a folder onto Duplicate Finder and click Find. It compares file contents and lists every set of identical files, with how much space the extra copies take.

**How does it know two files are duplicates?**
It compares the actual contents, not names or dates, so only true copies are matched, even if they have different names. Similar-looking photos are found too if you turn that on, but they're only reported, never moved.

**Will it delete anything without asking?**
No. By default it only makes a report. If you choose Move extra copies to the Trash, one copy of each set is kept and the others go to the Trash, so you can put them back.

**How do I find duplicate photos on a Mac?**
Drop your photo folders in and turn on Also find similar-looking photos. You'll see exact copies plus resized or re-saved versions of the same picture.

**Which copy does it keep?**
The one you choose under Keep: the best copy (outside Downloads, then the oldest), the oldest, the newest or the one with the shortest name. Every other identical copy in the set is moved to the Trash.

**Does it search inside my Photos library?**
No. The Photos library is a package and is skipped, because removing files from inside it can damage the library. Use Photos' own duplicates album for those.

**Can I search an external drive?**
Yes. Drop the drive or a folder on it. Files moved to the Trash from an external drive go to that drive's Trash.