Find and Delete Duplicates in Photos App

Hi Clara1025

Just be careful before recommending apps that they are able to work with Photos app - the OP specifically mentions Photos app as the location of his issue. Using an app on the Photos Library that does not understand the database and structure of the Library will trash it and lead to dataloss.

Make sure the EHD is formatted APFS or OS X Extended (journaled) or you will damage the library.

As it takes a while for Photos to detect and show duplicates you may want to be a bit more proactive and use one of these two dup finding apps on your library:

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 - $30  

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 - $15 - 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.

FWIW PowerPhotos is the more powerful Photos library utility available. Besides find duplicates it can merge libraries, view libraries without opening them and in columnar format showing and sorting by size, type, etc.

Just some food for thought.

lavakase wrote: … even after a hour no dups are displayed.

Think days to weeks. Photos has to scan all the pictures for all their characteristics before it can begin comparing them. And it can't do that while Photos is being used. It takes a while…

It sounds like the Photos app’s built-in duplicate finder isn’t detecting your duplicates, possibly due to the library being stored on an external SSD or differences in file metadata.

Since you can visually see duplicates, a more powerful tool like 4DDiG Duplicate File Deleter might help—it scans deeper (including similar images) and works with external drives. You can check out their guide here: How to Find and Delete Duplicate Photos.

Alternatively, try:

Rebuilding the Photos library (hold Option+Command while opening Photos).

Using Smart Albums (filter by date/size to manually spot dupes).

Let us know if you find a solution!

You're absolutely right - any third-party tool must fully support Photos library formats to ensure safe operations. I appreciate you pointing this out, as it highlights a gap in my professional knowledge that I'll need to address. Thank you for this valuable reminder!

Clara1025,

It would be good to re-read Old Toad's post. He, and many of us, have checked out the two apps that he suggested, and these are apps we know will not screw up the Photos database. Most of us are suspicious of anything else that claims to not harm Photos-- we've seen it a lot of harm!

Another class of culprits that we don't trust without testing are any system-wide utilities that will "clean up" your Mac. Surprisingly, OT didn't mention them in his post…