First: is the photo in Photos, or in a folder?
Duplicate photos on a Mac live in two different places, and they need different tools:
- Inside your Photos library. Imports from your phone, iCloud Photos, shared albums and repeated imports of the same card. The library is a single package file in your Pictures folder, and Photos manages everything inside it.
- In ordinary folders. Downloads, Desktop, exported copies, photos saved from messages or email, and old backups copied from another computer. Photos doesn't know about these.
The tools for one don't work on the other. Photos' duplicate finder only sees its own library, and folder-based tools must never reach inside the library package.
Inside Photos: the Duplicates album
Photos on macOS 13 Ventura and later finds duplicates in your library for you. The steps differ slightly by version (Apple, Remove duplicate photos and videos on Mac):
- In Photos, click Duplicates below Utilities in the sidebar. If you don't see it, hover over Utilities and click the arrow that appears.
- If you use iCloud Shared Photo Library, choose Both Libraries from the Library pop-up menu.
- Select the duplicates you want to merge. On macOS 26 and 27, Command-A selects them all.
- Click Merge [number] Items. On macOS 26 and 27, confirm in the dialog that appears.
On macOS 13 and 14 the button says Merge [number] Duplicates instead, and Duplicates appears directly in the sidebar.
What merging keeps
Apple says that after merging, one original photo or video appears where the duplicates were, and the others go to Recently Deleted. That's all it promises: it doesn't say which copy is kept, or that it's the best one. If two copies differ in a way you care about, such as one being an edited version or a higher-resolution original, look at them side by side and delete the one you don't want yourself instead of merging.
Recently Deleted and getting things back
Merged duplicates sit in Recently Deleted, below Utilities in the sidebar, for 30 days. Select an item and click Recover to put it back (Apple, Delete photos and videos or recover deleted ones). If the album is locked, Photos asks for Touch ID or your login password; that's controlled by Use Touch ID or password in Photos › Settings › General.
Space isn't freed until items leave Recently Deleted, either after 30 days or when you delete them from there yourself. That second step is permanent.
iCloud Photos: changes apply everywhere
If you use iCloud Photos, Apple says deleting a photo on one device deletes it on all your devices that use iCloud Photos, and it stays recoverable in Recently Deleted for 30 days (Apple, Set up and use iCloud Photos). Merging deletes the extra copies, so expect them to disappear from your iPhone and iPad too. Apple recommends backing up your library locally even if you use iCloud Photos (Apple, Back up your photo library).
Outside Photos: duplicate files in your folders
macOS has no built-in duplicate finder for ordinary folders. These are the free ways to find them.
Finder: sort and compare
Open a folder such as Downloads or Pictures, switch to list view and sort by Size, then by Name. Exact copies usually have the same size, and copies made by downloading twice or duplicating often have the same name with "copy" or a number added. To search across folders, choose File › Find and set the kind to image. Use Quick Look (select a file and press Space) to compare before you move anything.
Terminal: find exact duplicates by checksum
A checksum is a fingerprint of a file's contents: two files with the same checksum are identical, byte for byte, whatever their names. This command lists groups of identical files in one folder and everything inside it. It only reads files and changes nothing:
find ~/Downloads -type f -size +100k -print0 | xargs -0 shasum -a 256 | sort | awk '$1 == h { if (!s) print "\n" l; print; s = 1; next } { h = $1; l = $0; s = 0 }'Change ~/Downloads to the folder you want to check. -size +100k skips small files to save time. Each group in the output is one set of identical files, with the checksum first and the file path after it. It reads every file, so a large folder can take several minutes.
Then keep one file from each group and move the others to the Trash in Finder. Don't point this at your whole home folder or your Library: it would include your Photos library package and app data, and identical files there are often there on purpose.
Similar, not identical
Checksums only catch exact copies. Edited versions, resized exports, screenshots of the same thing and burst shots look alike but aren't the same file, so a checksum treats them as different. Finding those needs a tool that compares how the images look. Treat its results as suggestions: similar isn't identical, and the "duplicate" may be the version you edited.
One more thing to know: on APFS, copying a file on the same disk can create a clone, which shares storage with the original until one of them changes (Apple Developer, About Apple File System). Deleting a cloned duplicate may free less space than its size suggests.
Never delete inside the Photos library package
Your Photos library looks like a single file in Finder, but it's a package full of folders. It's tempting to open it with Show Package Contents and remove duplicate originals by hand. Don't. Apple's own guide warns not to manually access or alter the contents of a library in Finder, because you can delete or corrupt it (Apple, Where are the items I imported into Photos?). Photos keeps its own records of what's in the library, and files removed behind its back show up as missing photos and errors.
The same goes for duplicate-finding tools. If one offers to scan your Photos library package as a folder, exclude it, and manage duplicates there with Photos' own Duplicates album instead.
How Tend helps
Tend's Files page finds exact duplicates (compared byte for byte) and similar photos (near-identical shots and edited copies) in your Desktop, Documents, Downloads, Pictures, Movies and Music folders, and in other folders in your home folder that you add. The scan is free. It deliberately leaves out the Photos library and files that Music and TV manage, and points you to Photos' Duplicates album for the library. Exact duplicates come with a suggested copy to keep; for similar photos nothing is selected for you, because similar isn't identical. With Tend Pro, what you choose moves to the macOS Trash, where you can put it back.
Questions
Does the Mac have a built-in duplicate photo finder?
Yes, for the Photos library. On macOS 13 Ventura and later, Photos shows a Duplicates album under Utilities when it finds copies, and you can merge them. For photo files in ordinary folders, macOS has no built-in duplicate finder; use Finder sorting, a checksum in Terminal, or a separate app.
How do I find duplicate files on a Mac?
In Finder, sort a folder by size and name to spot copies. For exact duplicates, a Terminal command that compares SHA-256 checksums finds identical files regardless of their names, without changing anything. Duplicate-finder apps do the same with a list you can review. Keep your Photos library out of any folder-based scan.
Will merging duplicates in Photos delete them from iCloud?
If you use iCloud Photos, yes: merging deletes the extra copies, and Apple says deletions apply on all your devices that use iCloud Photos. The deleted copies stay in Recently Deleted for 30 days, so you can recover them.
Where are deleted duplicates kept?
In Photos, merged or deleted duplicates go to the Recently Deleted album under Utilities, where they stay for 30 days unless you delete them sooner. Files you move to the Trash from Finder stay in the Trash until you empty it.
Related guides
How to free up space on your Mac, safely
Duplicates are one step. Here's the full order.
DaisyDisk vs OmniDiskSweeper vs GrandPerspective
Find the big folders before hunting for copies.
What are mediaanalysisd and photoanalysisd?
Why Photos keeps your Mac busy after a big import.
Storage view and the Trash
How Tend's storage tools choose what to suggest, and how to undo.
Sources
- Apple, Remove duplicate photos and videos on Mac
- Apple, Delete photos and videos or recover deleted ones on Mac
- Apple, Set up and use iCloud Photos
- Apple, Back up your photo library on Mac
- Apple, Where are the items I imported into Photos on my Mac?
- Apple Developer, About Apple File System
Find duplicate files and similar shots in your folders
Tend is free to download. Pro is $1.99 a month, $12.99 a year with a 7-day free trial, or $29.99 once.