Duplicate photos in Apple Photos

The duplicate detection is only available in macOS Ventura or later. If your Mac is compatible with macOS Ventura or later, you can upgrade from macOS Big Sur to macOS Ventura or later so that you can use the built-in duplicate detection to find duplicates in your Photos.

If you don't want to manually look for duplicates, you can use a duplicate photo finder app. As far as I know, there are many apps that can find duplicate photos on a Mac. But note that some of them support Photos and some (such as dupeGuru, an open source duplicate file finder) don't. An app called Cisdem Duplicate Finder supports Photos. In addition to photos that are exactly the same (regardless their names), it finds photos that look the same but are different in formats, dimensions, file sizes or metadata. It can also find similar photos and the slightly edited versions of the same photo. You can use this app to scan your photo library.

Duplicate detection was introduced to Photos with Ventura, Big Sur won't have a "Duplicates" album.

Before Ventura,, to deal with duplicates, many people used the 3rd party app, PowerPhotos ($30), one of the very few apps that we can trust to work properly (for 20 years!) with Photos. I still use it for duplicates sometimes-- different algorithms give slightly different results, and it's useful to double check. If you must stick with Big Sur, then PowerPhotos adds great utility for Photos.

john8635 wrote: An app called Cisdem Duplicate Finder supports Photos.

I did not see anything on their website that said that Cisdem supports the Photos app, and their App Store blurb doesn't mention the Photos app. Very very few apps work with Photos, and at least do it well. I did see a review that said it worked with Photos, but I'd be very suspicious. The Photos app relies on a database that keeps account of all the pictures, their file location, their metadata, and so on. If a file is changed without the database being involved, then the whole Photos Library will become corrupted.

I mentioned PowerPhotos ($30) in an earlier post, because it has been used and tested for 20 years. It uses Photos itself to do the work, so the database is taken care of. We've seen 3rd party apps that mess around inside the Photos package really screw up the Library. Corruption also happens with those useless "Cleaner" apps that charge you money to do things that the Mac already does for you.

The other Duplicate app that I've seen that people have successfully tested is PhotoSweeper which is available for $10 in the App store-- it's blurb does say that it works with the Photos app.

With Big Sur your best options for culling out duplicates are the following:

You want an app that will identify the potential duplicates, put them in an album or mark them with a keyword for easy retrieval and deletion by you. You don't want one that does the deletion itself for obvious reasons. 

I've run tests on the these two apps with the following results and found them to be safe to use:

PowerPhotos - $29.95  

PowerPhotos is the iPhoto Library Manager version for Photos and is very powerful. Although more expensive I would recommend it as it has more capabilities than the others like the capability to merge Photos libraries or copy photos, both original and edited versions, along with their metadata between libraries.

PhotoSweeper - $9.99 - Demo version available.

PhotoSweeper compares bitmaps and/or histograms so it can detect duplicate images even if they have different file sizes, file names, image sizes and capture dates.

I've been using Cisdem Duplicate Finder for over five years. Its support for Photos was the exact reason why I chose it. And the website does say that it works with Photos/iPhoto.

It's true that not many apps support Photos. The good news is some apps do support it. If I hadn't come across Cisdem Duplicate Finder, I would have been interested in checking out the app you recommended. I'm pretty happy with Cisdem Duplicate Finder so far.

john8635 wrote: I would have been interested in checking out the app you recommended. I'm pretty happy with Cisdem Duplicate Finder so far.

Glad to hear that there is another app that works. I still haven't found a statement that it really works in Photos-- the App Store blurb says it will find duplicate files in Photos, but it doesn't speak specifically to picture files or how it preserves the database. I've got to say that I'm always turned off by "In-app purchases" and "subscriptions." You've had a good experience, so that's useful data. Thanks.