Duplicate Cleaner For iPhoto 4+

Platform MacOS Big Sur. A different review mentioned this app would put selected photos in a "review" folder before trashing them. There is a dialog that asks whether or not the user would like to review or trash, but when I selected "review" nothing happened. So I selected Trash as I was sure I didn't need these duplicates, and it excuted the command. Otherwise I recommend this app, it works great except for that one feature, and it provides all the info necessary to make the selection decision very easy. No digging around in submenus for info. I would give it 5 stars, but I don't see how the review function is useful, as it doesn't seem to work as I expected.

I know, you’ve got to trust an app in order to let it remove your pics. I was hesitant, however all it does is identifying first the duplicates, probably by looking at different things, including the EXIF and maybe some sample pixels, I don’t know. Once you confirm that it did identify the duplicates correctly, it is going to move them all in a duplicates album in photos.
Then you can go there, review them again and just select all the photos you want to delete. Then the photos go to the deleted photos album of Photos, so you’ll have yet one more chance to correct any mistake. Obviously I could not review 6000 photos one by one in 5 minutes, however I did verify samples and they were OK, plus I identified some of the duplicates I knew I had.
I’ll be honest, I’m not sure why I ended up with so many duplicates, it’s probably because of all the iCloud syncing between different devices, however I feel better now.

We saw recommendations for this app in a search and then downloaded it from the AppStore. It was up and running immediately - there is virtually no setup. Just pick the library or folder that you want to scan and go. It took just a couple of minutes to scan Photos library (over 237GBs) and then displayed the duplicates side by side (there were up to five duplicates of some photos). It was easy to review the 2064 duplicate photos before deleting.

The deletion process was a little unusual, as it requires you to open Photos, where it will move the duplicates to a new folder named "Duplicate Marked Photos”. It’s up to to make the final decision to delete them from your library. I imagine that limits their liability, but it also gives you one last chance to decide to keep them. You could even export them to a hard drive - just in case - while still cleaning up your library.