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Migrating to a New Mac over a Cable: Migration Assistant or Manual Copy?

Updated 2026-09-21

A new Mac arrives, and with it the question: how do you move 500 GB, 1 TB, 2 TB of photos, projects and documents onto it without losing a night? Two answers complement each other: Apple's Migration Assistant for the system, and a Thunderbolt cable for everything else.

Migration Assistant: for accounts and apps

Migration Assistant copies your user account, apps, settings and files from the old Mac, a Time Machine backup or a disk. It's good at rebuilding your environment; less so at speed and flexibility:

• It defaults to Wi‑Fi, which can take hours. Since macOS Sonoma/Sequoia it uses a Thunderbolt cable if it finds one — plug it in before launching the assistant; it's five to twenty times faster.
• It runs once, one way, and neither Mac is usable meanwhile.
• It doesn't let you choose finely: a whole account, or a whole category.

Tip: do the system migration with the assistant over the cable, ticking only the account and apps; leave the big folders (Photos, video, projects) for later, to copy at your own pace.

The Thunderbolt cable: for data, at your pace

Once both Macs are set up, link them with a Thunderbolt 3, Thunderbolt 4 or USB4 cable. macOS creates a Thunderbolt Bridge at 10‑40 Gbit/s; with File Sharing, each Mac sees the other's disks in the Finder. You copy what you want, when you want, in both directions, while keeping both machines in use.

DiskBridge makes that immediate: installed on both Macs, it mounts the other's disks as soon as the cable is plugged in, and unmounts them when you pull it. A 300 GB Photos library moves in 3 to 5 minutes between two SSDs; over Wi‑Fi, plan an evening.

The plan that works

1. Before: update the old Mac, make a Time Machine backup (just in case), note your app licences.
2. System migration over the cable: plug in the Thunderbolt cable, launch Migration Assistant on the new Mac, choose "From a Mac", tick only the account, apps and settings.
3. Data with DiskBridge: install DiskBridge on both Macs; the old Mac's disks appear in the new Mac's Finder. Copy Photos, Music, Movies, projects, virtual machines — folder by folder, checking as you go.
4. After: keep the cable handy. As long as the old Mac is around, it becomes a backup disk or a second workstation; DiskBridge makes the exchange permanent.

Special cases

• Old Intel Mac, new Apple silicon Mac: everything above works, provided the Intel Mac has Thunderbolt 3 (2016 and later). With Thunderbolt 2, use Apple's Thunderbolt 3 ⇄ 2 adapter; the DiskBridge app won't install on macOS 12 and earlier, but the old Mac can still be reached from the new one through File Sharing.
• Old Mac that no longer boots: Recovery › "Share Disk" (see Target Disk Mode on Apple silicon), or pull the internal disk — no magic cable here.
• Photos library: copy the whole .photoslibrary package, never its contents; then open it with Photos while holding ⌥.

What you need

A Thunderbolt/USB4 cable (which one?), both Macs, and DiskBridge — the 14‑day trial easily covers a migration; the one‑time purchase (US$4.99) then serves all your Macs.

More guides

• How to Connect Two Macs with a Thunderbolt or USB‑C Cable (2026)

  How to link two Macs with a Thunderbolt 3, Thunderbolt 4 or USB4 cable, set up Thunderbolt Bridge and see the other Mac's disks in the Finder — manually, or automatically with DiskBridge.

• DiskBridge vs Intel Thunderbolt Share — Linking Two Computers with a Cable, on Mac and on PC

  Intel Thunderbolt Share lets two Windows PCs talk over a Thunderbolt cable; DiskBridge does the same between two Macs. What each one does, what it costs, and why they are not interchangeable.

• Moving Video Footage from a MacBook to a Mac Studio Without an External SSD

  For editors and photographers — moving 4K/8K footage, RAW libraries and Final Cut, DaVinci or Lightroom projects from a laptop to a desktop workstation at Thunderbolt cable speed.

• Target Disk Mode on Apple Silicon Macs: What Changed, and the Alternative

  Target Disk Mode is gone on M1, M2, M3 and M4 Macs. What Apple offers instead (Share Disk), its limits, and how to get direct access to another Mac's disks over a cable again.