Before you copy your iPhoto photos to an external hard drive
To copy iPhoto photos to an external hard drive, you move the entire Photos Library file rather than exporting individual images. This preserves your albums, faces, and edits while freeing up space on your Mac’s internal drive. The process requires four steps: prepare the drive, locate the library, copy it, verify it, and only then delete the original.
Before you begin, quit the Photos app completely. If Photos is running while you copy its library file, you risk a corrupted or incomplete transfer. Also, confirm your external drive is formatted as APFS or Mac OS Extended (Journaled). These are the only formats macOS fully supports for a Photos library. If your drive uses another format, you’ll need to reformat it first, this erases everything on it, so back up any existing files. If you use a cloud service, you can also transfer photos from Amazon photos to external hard drive for an extra backup.
Additionally, do not store your Photos library on a storage device used for Time Machine backups, removable media like SD cards or USB flash drives, or on a network or cloud-shared device. Time Machine disks have special permissions that interfere with Photos, and removable or network storage is too slow or unreliable for an active library. Finally, open the external drive’s Get Info window (select it in Finder, press Command+I) and ensure the “Ignore ownership on this volume” checkbox is selected. This option may not be available if the drive is incorrectly formatted or was previously used for Time Machine, another reason to verify the format first.
Locate and copy your Photos library file
Your entire photo collection lives inside a single package file called “Photos Library.photoslibrary.” This file contains every photo, video, album, and edit you’ve made. To copy it, open a new Finder window and navigate to your home folder (Finder > Go > Home), then open the Pictures folder. You’ll see the Photos Library file there, it may appear as a single item with a photo icon, but it’s actually a folder containing everything.
Drag the “Photos Library.photoslibrary” file to your external hard drive. This copies the library, not moves it, your original remains on the Mac until you delete it later. Depending on the size of your library and the speed of the drive, this copy may take several minutes or longer. Do not interrupt the transfer. When the progress bar disappears, the copy is complete. If you want to organize Google photos later, having the library as a single file makes it simple to move or back up again, and you can similarly transfer Google photos to external hard drive for a unified offline backup.
Open and verify the copied library
After the copy finishes, double-click the “Photos Library.photoslibrary” file on your external drive. Photos will launch and open this library. Confirm that your albums, faces, and recent imports appear exactly as they did on the original. Scroll through a few random photos to ensure nothing is missing or corrupted. If you use iCloud Photos or want other applications to access this library, you must designate it as the System Photo Library. Go to Photos > Settings (or Preferences) > General and click “Use as System Photo Library.” Only the System Photo Library can send or receive photos and videos via iCloud Photos, so this step is essential if you rely on iCloud syncing.
If you ever need to switch between libraries, quit Photos, press and hold the Option key while opening the Photos app, and select the desired library from the list. This is useful if you keep a smaller library on your Mac for recent work and the full archive on the external drive. Note that if the external drive containing your Photos library is disconnected when you open Photos, the app will create a new, empty library in the default Pictures folder. Always reconnect the drive before launching Photos to avoid accidental creation of a separate library.
Delete the original library to free up space
Only after you have verified that the Photos library on the external drive is working correctly can you delete the original “Photos Library.photoslibrary” file from your Mac’s internal drive. Drag it from the Pictures folder to the Trash, then empty the Trash. This permanently frees up the storage space that your photo library was occupying. Before you do this, double-check that the copied library opens without errors and that you’ve designated it as the System Photo Library if you need iCloud access.
Once you delete the original, your Mac will no longer have a local copy of your photos. The external drive becomes your primary photo storage. If you want an extra layer of safety, consider making a second copy of the library on another drive or a cloud service. But for day-to-day use, the external drive is now your photo home. Every time you connect the drive and open Photos, you’ll see your full library. When the drive is disconnected, Photos will show an empty library, so make a habit of keeping the drive connected when you want to browse or edit photos.
If you ever need to access your photos on a different Mac, connect the external drive and hold the Option key while opening Photos to select the library. The same process works for moving the library back to an internal drive if you upgrade your Mac or change your storage setup. The key is that the library file remains intact and self-contained, it carries all your metadata, edits, and organization with it. This is why copying the entire library file, rather than exporting individual photos, is the correct approach. You preserve everything, including the structure you’ve built over years of capturing memories.
After emptying the Trash, verify your Mac’s available storage has increased by the expected amount. If the space hasn’t freed up, check that the Trash is actually empty and that no other copies of the library exist elsewhere on your internal drive. You can also use Finder’s search to look for “Photos Library” to ensure no stray copies remain. Once you confirm the space is reclaimed, your migration is complete. Your photos are safely stored on the external drive, your Mac has room to breathe, and you can continue adding new memories without worrying about running out of space.
