How to Delete Duplicate Photos in Mac OS X Photos App Easily

2020-08-07 05:22:00 / Posted by Rosa Reyes to Utility Follow @ Rosa

Known as Mac OS X from 2001 to 2012, OS X from 2012 to 2016 and macOS since 2016, the operating system for Apple’s Mac computers always comes with useful preinstalled apps like Photos (previously iPhoto until 2015). Apple OS X Photos is an easy-to-use yet powerful app to browse, organize and manage photos.

As with any apps, it’s not perfect. Duplicate photos are one of the most common issues with the Photos app. How do I delete duplicate photos in OS X Photos? You will find the best answer in this guide.

Why does Photos duplicate photos when importing?

Apple Photos for Mac allows you to easily import photos from an iPhone, a digital camera, an external storage device or a regular folder on Mac. Photos app could duplicate photos when importing sometimes. Below is a common scenario or reason.

When you import photos from iPhone to Mac Photos app, you use the function Import All New Photos, which will recognize the new photos and import them. This function works fine most of the time.

However, suppose that all the old photos on your iPhone are converted from the original format to a different format such as HEIC. The next time, when you use the Import All New Photos function when importing photos from iPhone, OS X Photos app will consider these converted old photos as new ones and import them all. The old photos end up duplicated in Photos app.

How to remove duplicate photos from Photos library, automatically and safely

By default, the photos imported to your OS X Photos app are stored in the Photos library in your Mac’s Pictures folder. As a result, if you want to delete duplicate photos on Mac photos app, you need to remove duplicates from the Photos library. It’s possible to do the removal manually. But you won’t want to try it if there are hundreds, thousands or more items in your library!

The best way is to use duplicate photo finder software to automatically identify them so that you don’t have to browse through numerous photos and manually locate duplicates. For this guide I use Cisdem Duplicate Finder, which is considered the best duplicate photo finder Mac 2020 by many Mac users.

Cisdem Duplicate Finder uses advanced algorithms to quickly detect duplicate photos based on content regardless of filename. After that, it lets you decide which photos to delete and which to keep. Mac Photos will ask if you allow this duplicate photo finder to delete the unwanted duplicates. The deletion won’t happen until you grant the permission. The whole process adheres to the mechanisms of Photos app, which is absolutely safe and reliable.

Below are the steps to remove duplicate photos from Photos library easily and quickly.

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  1. Download and install Cisdem Duplicate Finder for Mac.
  2. Open the Photos app. From the menu bar, select Photos > Preferences.
  3. Under General tab, make sure that the library shown there is the library in which you'd like to find duplicates.
  4. Set it to be the system photo library. If the Use as System Photo Library button is grayed out, then it's already set to be so.
  5. Open this Mac Photos duplicate finder.
  6. Click the plus icon +. Click Pictures folder in Finder's sidebar and select your Photos Library. Click Photos Library to open
  7. Click Scan.
  8. Read the message and click Yes.message
  9. Once the scan is done, choose Images tab. View, sort and preview duplicate photos as you like.preview duplicate photos
  10. The Auto-Select function automatically selects duplicates for you to delete with one click.
  11. If you are not happy with auto-selection, click the list icon and select a desired selection rule.delete duplicate photos in os x photos
  12. Click Delete.
  13. When asked if you allow the deletion, click Delete to allow.

Note: If your MacBook Pro, MacBook Air or iMac, etc. is running on macOS 10.14 Mojave or earlier, then Step 4 and Step 9 will be different.

As for Step 4, once you click Scan scan button, a message will pop up asking you to open the OS X Photos app. Click Open to continue.

As for Step 9, it will require a couple of more steps. When you click Delete in Step 8, a new window will show up telling you how to complete the final deletion. In your Photos app, open the album called Cisdem Duplicate Album. Select the items (which are the unwanted duplicate photos) in it and right-click on them. Choose Delete ... Photos. In Recently Deleted, select the photos there and click Delete All in the top right corner.

Tips to automatically delete duplicate photos in OS X Photos

If you have multiple Photos libraries, before the whole process, you need to first designate the System Photo Library in Photos. Here’s the detailed guide to do this.

In addition to exact duplicate photos, the Mac Photos duplicate finder I use above can also identify and delete similar images. In Step 5, choose Images > Similar. When you click the list icon, you will be finding 7 selection rules to batch select undesirable duplicates for removal.

How to delete duplicate photos on Mac Photos manually

You can choose to delete duplicate photos in OS X Photos app by hand if there are only a few photos in your Photos library.

  1. In Apple Photos app on your Mac, choose Library > Photos.
  2. Click the Photos tab at the top. Make sure it is showing all photos.
  3. Press and hold the Command key and select the unwanted photo duplicates by hand.
  4. When you are done selecting, perform a right-click. Click Delete ... Photos.delete duplicate photos
  5. Go to Recently Deleted. There, select all the items and click Delete All.

Tip to delete duplicate photos in Photos by hand

Mac OS X Photos has a function called Smart Album. If you need to find out the duplicates among a certain type of photos rather than all your photos in Photos library, this function can help.

Hover your mouse over My Albums, and a plus icon will appear. Click it and choose Smart Album. Name this album and create one or more conditions. Click OK. Photos that fall into this condition or combination of conditions will appear in this Smart Album.

Now create a regular Photos album and put these photos in to it. Browse through these photos, identify duplicates and select the unwanted ones for elimination.


Removing duplicates from Mac Photos app can reduce Photos library size, which helps free up space on your Mac. Also, keeping your Photos app from duplicate photos can also offer a better browsing experience. The methods recommended in this guide are easy to follow. They apply to various versions of Photos app, from the earlier ones to Photos 5.0 which comes with OS X 10.15 Catalina.

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