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Back up iPhone to an external hard drive on Mac

Backups · · 7 min read

To back up an iPhone to an external hard drive on a Mac, Finder needs a filesystem workaround: copy its Backup folder to the drive, then replace the original folder with a symbolic link. Finder has no backup-location setting, so the drive must stay mounted at the linked path whenever you back up or restore. Yado lets you choose a backup folder in Settings instead, without redirecting Finder's folder.

How the backup location works

Apple stores Finder backups at this path, which you can open with Go, then Go to Folder in Finder:

~/Library/Application Support/MobileSync/Backup/

A symbolic link is a filesystem entry containing another path. When software opens it, macOS follows that path, including across disks. Finder still addresses its usual Backup folder, while the files live on the external drive. Redirecting this parent folder affects the backups inside it for all devices, so keep the entire folder together.

This is a workaround based on macOS link behavior, outside Apple's documented backup workflow. If internal storage is sufficient and you only need an occasional local backup, Finder alone is enough. The guide to backing up iPhone to Mac covers that simpler route.

Prepare the external drive

For a drive dedicated to Mac backups, use APFS. Apple's Disk Utility format guide says APFS supports external, directly attached storage and traditional hard disks as well as SSDs. ExFAT is useful for Windows compatibility, but it does not provide the file cloning that Yado uses for kept backup copies.

Select the drive in Finder and press Command-I to check its format. Reformatting erases data, so copy anything needed elsewhere before changing formats. Leave room for the existing backup and future changes, rather than sizing the disk for today's backup alone.

Time Machine is a separate backup system. If the same physical drive also holds Time Machine backups, Apple says to create an additional APFS volume for other files. Put the iPhone backup on that separate volume.

Redirect Finder's Backup folder

The example below uses a volume named iPhoneBackup, with a folder named Backup at its root. Substitute your actual volume name everywhere, preserving the quotation marks around paths.

  1. Finish any running backup or restore before copying files. In Finder, open Go, then Go to Folder, and enter ~/Library/Application Support/MobileSync/.
  2. Copy the whole Backup folder with Command-C, open the external drive, and paste with Command-V. Wait for copying to finish. The result should be /Volumes/iPhoneBackup/Backup, with the device folders directly inside it, not another nested Backup folder.
  3. Back in MobileSync, select the original Backup folder, press Return, and rename it Backup-local-before-move. Keep it as a fallback. If that name already exists, stop and identify the earlier copy rather than replacing it. If Backup is already a symbolic link, inspect that setup before changing it.
  4. Give Terminal access to the protected backup location in System Settings, Privacy & Security, Full Disk Access. Add Terminal if necessary and enable its access. This permission allows broad file access, so turn it off again after finishing the Terminal steps if you do not otherwise need it.

If you have never made a Finder backup and these folders are absent, use Finder to create MobileSync inside ~/Library/Application Support/ and an empty Backup folder on the external drive. Skip the copy and rename steps, keeping the local MobileSync folder ready to contain the link.

In Terminal, create the link only when the local name Backup is available:

ln -s "/Volumes/iPhoneBackup/Backup" "$HOME/Library/Application Support/MobileSync/Backup"

The first path is the destination holding the files; the second is the link being created. Keep the local MobileSync folder itself in place. If a real Backup directory still occupies the second path, ln can place a link inside it instead of replacing it.

Check the link:

readlink "$HOME/Library/Application Support/MobileSync/Backup"

It should print /Volumes/iPhoneBackup/Backup. Also open that external folder in Finder and confirm its contents. A correct-looking link does not prove the destination exists or the backup is complete.

Connect the iPhone, select it in Finder, and click Back Up Now. Wait for completion and check that Finder's latest backup date and time update, as described in Apple's backup instructions. Under General, open Manage Backups, then use Show In Finder on the backup to inspect where its files reside. Keep the original local copy until these checks pass, then remove that fallback only when you are ready to reclaim its space.

Check failures before changing the link again

An unplugged or renamed drive leaves the link pointing at a path that is unavailable. Mount the drive and confirm the exact volume and folder names first. The link does not automatically select a different disk, and you should not assume Finder has fallen back to internal storage.

If readlink prints nothing, stop before running any removal command. The path may be a real folder, missing, or inaccessible. If link creation reports an existing item, inspect the local MobileSync folder, including for an accidentally nested Backup link, rather than adding force options.

For permission or write failures, separate Terminal's access to MobileSync from write access to the external destination. Try copying an ordinary file to the destination folder in Finder. Apple's external-drive troubleshooting covers format, free space, permissions and disk errors. A readable drive is not necessarily writable.

Undo the Finder workaround

Finish all backup activity and make sure the Mac has room for the current external backup. In Finder, copy the external Backup folder into a new temporary folder inside MobileSync, such as Backup-return. This keeps the new copy separate from both the link and the older local fallback.

Run the readlink check above again. Only if it prints the external destination you intend to disconnect, remove the link with this exact command, without a trailing slash:

unlink "$HOME/Library/Application Support/MobileSync/Backup"

This removes the symbolic link, leaving its external destination intact. Move the copied Backup folder out of Backup-return into MobileSync, so a real folder occupies the original path. Check Finder's backup list and run a backup again. Use the current external copy when returning; the saved local fallback predates any backups made after redirection.

Choose the destination directly in Yado

In Yado, open Settings, find Backup Location, click Change, select a folder on the external volume, and click Choose. This setting controls Yado's backup directory, independently of Finder. Its default is ~/Library/Application Support/Yado/Backups.

From Overview, click Manage on the backup card to open Backup, then click Start Backup. For a first backup, Yado checks the estimated space required against available space on the disk holding the selected folder, when those values can be read. If the estimate exceeds available space, Choose Folder lets you select another destination, then repeats the check. This estimate is a preflight check, not a reservation of disk space or a guarantee against later write failures.

Under Keep backups, older copies use copy-on-write clones. They initially share file data blocks with the live backup, but subsequent writes are private to each file. Hard links would share the same underlying file, so an incremental backup overwriting it could also change the supposedly preserved copy. Yado deliberately uses clones and stops preservation if cloning fails, rather than substituting hard links. Use APFS if you want those earlier states, and keep free space for changed data.

Move an existing Yado backup

Changing Backup Location saves a path; it does not transfer existing backups. Finish all operations, copy the contents of the old backup directory into the new directory, keeping each device folder and kept copy intact, then select that parent directory in Settings. Budget for a full copy when transferring to another volume.

Close and reopen Backup to scan the selected directory. Confirm the expected entries under Existing Backups, then use each copied backup's More menu and Check Backup before removing the old copy. Encrypted backups need their password for that check. Browse Contents lets you inspect individual records; the guide to viewing an iPhone backup on Mac covers that step. If the list is empty, check for an extra folder level before assuming the backup is missing.