Merge Photo Libraries Mac: How to Combine Them

Yes, you can merge photo libraries on a Mac, and the safest method is to use the built-in “Import” feature in the Photos app rather than manually dragging folders in Finder. This article explains the two reliable approaches—using the Photos app’s Import command or the Migrate option in newer macOS versions—and walks you through the steps, what to watch out for, and how to avoid common pitfalls like duplicate photos and missing edits.

Why Merging Libraries Is Tricky

Photos on macOS stores each library as a package—a folder that contains the original image files, a database of edits and albums, and metadata like faces and keywords. When you open a library, the Photos app locks it, and other apps (including another instance of Photos) cannot access it. This locking is why you cannot simply copy the contents of one library into another. The database inside each library is also structured to reference its own files, so copying files directly can corrupt both libraries. The only officially supported way to combine libraries is through the app’s own import or migration tools, which read the contents and rebuild the database in the destination library.

Method 1: Import from Another Library (All macOS Versions)

This is the most straightforward method and works on every version of macOS that has the Photos app. You will open the destination library (the one you want to keep), then import from the source library.

1. Quit Photos completely (press Command+Q).
2. Hold the Option key and double-click the Photos app icon in the Applications folder (or in the Dock). A dialog appears asking you to choose a library.
3. Select the destination library (the one you want to keep all merged photos in) and click “Choose Library.”
4. Once Photos opens, go to File > Import.
5. In the file picker, navigate to the source library (usually in ~/Pictures). Right-click it and choose “Show Package Contents.”
6. Open the Masters folder (in older macOS versions) or the originals folder (in newer ones). Inside you will see subfolders with the actual image and video files.
7. Select all the files (Command+A) and click “Review for Import” or “Import Selected.”
8. Choose whether to copy the files into the library or leave them in place. Copying is safer because it keeps everything inside one library package.

After the import, Photos will scan the files, and any edits, albums, or faces that were in the source library will not transfer—only the original images and videos come over. You will need to recreate albums and re-assign faces manually.

Method 2: Use the “Migrate” Option (macOS Sonoma and Later)

Starting with macOS Sonoma (14), Apple added a dedicated migration tool. This method preserves more metadata, including edits and albums, but it is only available if both libraries are on the same Mac and you are using a recent version of macOS.

1. Quit Photos.
2. Hold the Option key and open Photos, then select the destination library.
3. In the menu bar, go to File > Migrate (or “Import from Another Library” in some versions).
4. Select the source library from the list that appears.
5. Follow the prompts. Photos will show you a summary of what will be imported (photos, videos, albums, and people).
6. Click “Migrate” and wait. The process can take a long time if the library is large.

This method is the closest to a true “merge” because it brings over your organizational structure. However, it may still create duplicates if the same photo exists in both libraries—Photos does not automatically detect and remove duplicates during migration.

Before You Merge: Backup and Clean Up

Merging is a destructive operation in the sense that if something goes wrong, you could lose data. Always back up both libraries before starting. You can copy the entire library folder to an external drive or use Time Machine. Also, check the total size of both libraries—merging two large libraries can take hours and require significant free disk space (at least double the size of the largest library). Finally, decide which library will be the destination. It is usually best to keep the one with the most recent edits or the one you use most often, because the destination library’s existing structure remains untouched.

What Gets Lost in the Merge

Even with the migration tool, some things do not transfer perfectly:

• Albums and folders may come over, but smart albums (which are based on search criteria) might not re-evaluate correctly.
• Faces are often not merged—you may need to re-confirm face identities.
• Keywords and titles generally transfer, but custom metadata may be dropped.
• Edits are preserved as a stack (original + edit) when using the Migrate option, but with the Import method, you only get the original, not the edited version.
• Shared albums and iCloud links are not merged; you will need to re-share them.

If you rely heavily on edits and albums, the Migrate method is far superior. If you only care about having all your photos in one place, the Import method is simpler and works on any macOS version.

Dealing with Duplicates

After merging, you will likely have duplicate photos—especially if you have been syncing with iCloud Photos on multiple devices. The Photos app has a built-in “Duplicates” album (under “Utilities” in the sidebar) that automatically detects exact duplicates. You can review and merge them manually. For near-duplicates (same photo with different edits or resolutions), you will need a third-party tool or manual comparison. A quick way to reduce duplicates before merging is to use the “Show Duplicates” feature in the source library and delete them there first.

Alternative: Use iCloud Photo Library as a Bridge

If both libraries are already synced to iCloud, you can avoid merging altogether. Turn on iCloud Photos on both Macs (or on the same Mac with two libraries), and let iCloud upload everything. Then on the destination library, enable “Download Originals” to pull everything down. This method is slow and requires enough iCloud storage, but it is automatic and does not require manual file handling. However, it can create duplicates if the same photo is in both libraries, and it may not transfer albums or faces reliably.

Frequently Asked Questions

Will merging delete any photos?
No, merging itself does not delete anything. The source library remains untouched unless you manually delete it after confirming the merge worked. However, if you use the Import method, the imported files are copies, so the originals stay in the source library.

Can I merge libraries from an external drive?
Yes, you can import from a library on an external drive. Just make sure the drive is connected and the library is not open in another app. The Migrate option may require the library to be on the same Mac, so the Import method is more reliable for external drives.

What if the Photos app says “Library is locked”?
This usually means another instance of Photos is running, or the library is on a network drive. Quit all Photos processes (check Activity Monitor for “Photo Library Utility” or “Photos”), and copy the library to your local drive before merging.

Do I need to merge libraries if I use iCloud Photos?
Not necessarily. If you have multiple libraries and all are synced to iCloud, you can simply switch to the library that has the most complete set and let iCloud download the rest. But if you want a single local library, merging is still the way to go.

How long does merging take?
It depends on the number of photos and the speed of your Mac. A library with 10,000 photos might take 30–60 minutes with the Import method, and longer with Migrate because it processes metadata. You can monitor progress in the Photos window.

Can I merge libraries without opening Photos?
No. There is no supported command-line tool or Finder drag-and-drop method. Attempting to copy the library package manually will corrupt the database. Always use the Photos app’s built-in features.

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