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Backup your iPhone on a NAS using a Mac

Guide•19 December 2025

Have you always wanted to backup your iPhone on a Network Attached Storage (NAS)? Have you ever needed to backup your iPhone on you Mac, but realized you've only got a 256GB SSD (most of it already full)? Are you tired of having iCloud Drive (and its monthly subscription) as the only backup solution?

Keep reading and I'll guide you on how to use an external storage (either physically connected to your Mac or in your local network) to always have your iPhone's data backuped.

The key to redirecting your iPhone backups is macOS's symbolic linking capability. Instead of changing how Finder works (which isn't possible), we'll trick it by replacing the default backup folder with a link to your external storage. When your Mac tries to save a backup to ~/Library/Application Support/MobileSync/Backup/, it will seamlessly follow the link to your NAS or external drive.

Prerequisites

Before we begin, you'll need:

  • An external drive or NAS with sufficient free space (at least 2-3x your iPhone's used storage)
  • The drive mounted and accessible from your Mac
  • Your iPhone and its USB cable (if you don't have Wi-Fi sync enabled)
  • Administrator access on your Mac

Step-by-Step Guide

1. Prepare Your External Storage

First, create a dedicated folder on your external drive or NAS share. For a NAS mounted via SMB, your path might look like:

"/Volumes/NAS/iPhone Backups"

or for a physical external drive:

"/Volumes/Time Machine/iPhone Backups"

Create this folder manually in Finder, or use the Terminal:

mkdir "/Volumes/NAS/iPhone Backups"

2. Locate and Move Existing Backups

Your Mac stores iPhone backups in:

"~/Library/Application Support/MobileSync/Backup"

Open the Terminal and check if you have any existing backups:

ls -la "~/Library/Application Support/MobileSync/Backup"

If you see folders with long hexadecimal names, those are your existing backups. Move them to your external storage to preserve them:

mv "~/Library/Application Support/MobileSync/Backup"/* "/Volumes/NAS/iPhone Backups/"

or skip this step if you don't care about them.

3. Remove the Original Backup Folder

Now delete the original Backup folder (not just its contents):

rm -rf "~/Library/Application Support/MobileSync/Backup"

or, if it says that you don't have enough privileges, use:

sudo rm -rf "~/Library/Application Support/MobileSync/Backup"

but be careful with this command.

This is the crucial step. The following command creates a link at the original location pointing to your external storage:

ln -s "/Volumes/NAS/iPhone Backups" "~/Library/Application Support/MobileSync/Backup"

Important notes about the command:

  • ln is the link command
  • The first path is your target (the external location)
  • The second path is the link name (where macOS expects to find backups)
  • Use "" quotes around paths containing spaces
  • No trailing slash after the target folder name

Check that the link was created correctly:

ls -la "~/Library/Application Support/MobileSync/"

If everything is correct, you should see output like:

lrwxr-xr-x  1 youruser  staff  32 Dec 19 10:30 Backup -> /Volumes/NAS/iPhone Backups

The l at the beginning of lrwxr-xr-x indicates it's a symbolic link. Good.

NAS-Specific Considerations

When using a NAS with SMB, ensure:

  • Mount persistence: Add your NAS share to System Settings → General → Login Items to auto-mount on boot
  • Permissions: The NAS share must be writable by your Mac user. Check SMB permissions on your NAS admin panel
  • Connection stability: Backups will fail if the network drops. Use a wired connection if possible
  • APFS/Sparsebundle: For best compatibility, format the NAS share as AFP or ensure it supports macOS metadata

Apple enables encrypted backups by default, and you should keep this setting. Encrypted backups include saved passwords, Health data, and other sensitive information. The symbolic link works identically for both encrypted and unencrypted backups (encryption is handled by the iPhone before data ever reaches your Mac).

To verify encryption is enabled:

  1. Connect your iPhone
  2. Open Finder (macOS Catalina or later) or iTunes (older macOS)
  3. Select your device in the sidebar
  4. Check "Encrypt local backup" under the Backups section

Troubleshooting

"Backup could not be completed" error:

  • Verify the external drive is mounted: ls /Volumes/
  • Check link integrity: readlink "~/Library/Application Support/MobileSync/Backup"
  • Ensure adequate free space on the target volume

Permission denied errors:

  • Run ls -la on your external folder to verify ownership
  • For NAS volumes, you may need to adjust SMB permissions or mount with specific options

Backups still appear on internal drive:

  • You may have created the link incorrectly. Delete it with rm "~/Library/Application Support/MobileSync/Backup" and repeat step 4 carefully

Reverting to Default Location

In case you need to switch back, simply:

rm "~/Library/Application Support/MobileSync/Backup"
mkdir "~/Library/Application Support/MobileSync/Backup"

then move any backups from your external storage back to the original location.

Conclusion

With this setup, every future iPhone backup will automatically be stored on your external drive or NAS, freeing your Mac's precious internal storage while keeping your data safe and accessible. This simple symbolic link trick transforms your backup workflow into a seamless, "set it and forget it" solution that works quietly in the background.

No monthly iCloud subscription required and no more worrying about SSD space or manually moving backup files. Your iPhone data flows directly to your chosen storage destination, encrypted and intact. Just remember to keep your external drive mounted or your NAS accessible before initiating backups, and occasionally verify that the connection remains stable.