How to find duplicate files on a Mac

By Little Mac Apps · Updated October 5, 2026

Short answer: macOS has no general duplicate-file finder. For photos and videos, open Photos and click Duplicates under Utilities in the sidebar (macOS Ventura or later). For everything else, use a tool that compares file contents. File Stacker's Duplicates tool groups identical files, lets you choose which copy to keep, and moves the others to the Trash.

Identical files vs. similar files

“Duplicate” can mean two different things, and they need different tools.

Kind	What it means	Example
Identical	The files contain exactly the same bytes, even if their names, dates or folders differ.	An installer downloaded twice; `report.pdf` and `report (1).pdf`.
Similar	The files look alike but their contents differ.	A photo and its edited or resized version; two burst shots; a song in two formats.

Identical files contain the same bytes, but their locations and metadata can matter. Before removing a copy, check that no app or project depends on it and that you’ve kept the metadata you need. Similar files need a person to compare them. File Stacker's Duplicates tool finds identical files only. It doesn't decide whether two different photos look alike.

What macOS can do on its own

Photos library: the Duplicates collection

Open Photos and click Duplicates under Utilities in the sidebar. If you don't see it, Photos may not have found any yet.
Select the duplicates you want to combine and click Merge.
One item stays in your library. The others move to Recently Deleted, where you can recover them for 30 days.

Never delete files from inside the Photos library package in Finder. Use Photos for anything in your library.

Other files: a manual check in Finder

Finder can't compare contents, but it can show likely duplicates. Search for a name, then switch to list view and sort by Size. Files with the same name and exactly the same size are worth checking. Open both before deleting, because the same size doesn't prove the same contents.

Find identical files with File Stacker

Scan the folders you want to check. Your Home folder is a good start; add an external disk with Grant Access to a Folder….
Open Duplicates in the sidebar.
Set Ignore files under to skip small files. A larger limit is faster and shows where the space is.
Run the search. Each set lists copies with identical contents, with the size of one copy and how many there are.
Choose the copy to keep, using the advice below, and move the others to the Trash.

To check a file before choosing, select it to see its full path and dates, or press Space for Quick Look.

How to choose which copy to keep

Keep the copy in the place you'd look for it. A file in an organized project or Documents folder is usually the one to keep. A copy in Downloads or on the Desktop is usually the spare.
Keep the copy an app depends on. Files inside a project folder, a code repository or an app's own folder may be referenced by path. Deleting that copy can break the project even though another copy exists.
Think about synced folders. Deleting a copy in iCloud Drive or another synced folder removes it from your other devices too.
Newest isn't always best. Identical files have the same bytes, so “newest” only means the most recently modified copy on disk. Choose by location and dependencies, not by date alone.
Keep the metadata you need. Finder tags, comments, the file name and dates aren't part of the contents, so two identical files can carry different ones. Copy anything you want onto the copy you keep before removing the others.

Why removing a duplicate may free less space than shown

File Stacker treats duplicate savings as an upper bound. You may get back less than the size shown because:

APFS clones share storage. When you copy a file on the same APFS volume, macOS can create a clone that shares the original's data blocks. Deleting a clone frees almost nothing.
Hard links point to the same data. Two paths can refer to one file on disk, so removing one path frees nothing.
Compression and sparse files mean a file can take up less space on disk than its listed size.
The Trash still holds the file. The space isn't available until you empty the Trash. File Stacker never empties it for you.

Undoing a mistake

Everything File Stacker removes goes to the Trash. Open Recent Removals and click Put Back to return an item to its original folder, as long as it's still in the Trash. In Finder, you can also select an item in the Trash and choose File → Put Back. You can also protect a folder so File Stacker won't remove anything inside it.

Sources

Apple Support: Remove duplicate photos and videos on Mac
Apple Developer: About Apple File System (clones and sparse files)
Apple Support: Free up storage space on Mac (emptying the Trash)
Apple Support: Delete files and folders on Mac (Put Back)