Before explaining how to delete Duplicate photos on Mac, let’s know :
There can be Duplicate photos on your Mac due to various reasons. It may happen that you have many photos on your Mac, so you upload a photo twice because of being unable to see it beforehand. There may be other reasons too, like involvement of third-party duplicate cleaner mac apps or bug.
If your library has a few photos, then you can find duplicates manually. But if the number of photos is very large, and as going through the library to check for duplicate photos isn’t a good idea, you can use a third-party app named Photos Duplicate Cleaner (available on Mac app store) for this purpose.
Step 1 : install Photos Duplicate Cleaner from the Mac App Store and then launch the app through the Applications folder.
Step 2 : When the app opens, click on the “Add Photos Library” option.
Step 3 : In the Finder browser that appears, double-click on your Photos Library to open it.
Step 4 : After processing your Photo Library, you should see its path appeared in the app’s path list. If it’s correct, click on the blue “Scan for Duplicates” option at the bottom of the app.
Step 5 : If your Photos app is still open, you’ll get a warning (as shown in the image below) . Click on the “Quit & Retry” option to close Photos and continue.
Step 6 : Open the Photos app , go to the Menu Bar and click View > Show Sidebar to enable the sidebar in the Photos app if it’s not already enabled.
Step 7 : Now with the sidebar enabled in the Photos app, click on the “All Photos” option in the sidebar (on the left).
Step 8 : Go back to the Photos Duplicate Cleaner app and you will see all duplicates. Go through these duplicates manually and select all the duplicate photos you want to delete. Un-selected photos will have a green border, and selected photos will have a red border.
Step 9 : After being sure of your choice, click on the blue “Trash Marked” button at the bottom of the app and it will transfer the duplicate photos into another folder named “Duplicate Marked Photos” in the Photos app.
When finished, the app will tell you it has completed its task.
Step 10 : Open the Photos app and you will notice the new “Duplicate Marked Photos” folder in the sidebar. Anything that appears in this folder is what Photos Duplicate Cleaner said it has deleted.
Step 11 : Select all the photos in this folder, right click on one of them, and click on “Delete X Photos” ( X = number of photos in the folder) from the menu list.
Kudos! All the duplicate photos have now been deleted from your Mac without much efforts.