Target Disk Mode on Apple Silicon Macs: What Changed, and the Alternative
For twenty‑five years, Target Disk Mode was every Mac user's reflex: boot a Mac holding the T key, link it to another over FireWire and later Thunderbolt, and it shows up as an external drive. On Apple silicon Macs, that mode no longer exists. Here is what Apple put in its place, why it's less convenient, and how to get an equivalent — better, actually — with a plain cable.
What Apple replaced it with
On M1 and later Macs, booting with the T key does nothing. The feature is now called "Share Disk" and lives in Recovery: hold the power button at startup › Options › Utilities › Share Disk. The Mac then shares its disk over SMB on the Thunderbolt (or USB) cable, and the other Mac connects through Finder › Network.
The differences from the old Target Disk Mode matter:
- The shared Mac is unusable meanwhile: it's in Recovery, not macOS.
- You must reboot to enter and leave the mode.
- The disk is shared over SMB, not mounted as a block device: you get the files, not the physical volume. Disk Utility doesn't see it, and neither do low‑level cloning tools.
- Sharing is one‑way and requires the password of an administrator account on the shared Mac.
Why Apple changed it
On Apple silicon, the internal disk is encrypted by the Secure Enclave and tightly bound to macOS. Exposing the raw volume to another computer is no longer possible without going through the system — hence network sharing from Recovery. It's a security constraint, not an oversight.
The alternative: Thunderbolt Bridge, no reboot
What most people wanted from Target Disk Mode — see the other Mac's disks and copy both ways, fast — still exists, with no reboot: Thunderbolt Bridge. A Thunderbolt 3, Thunderbolt 4 or USB4 cable between two running Macs creates a private 10‑40 Gbit/s network; with macOS File Sharing on, each Mac's disks are reachable from the other in the Finder while both machines keep working.
DiskBridge automates that scenario: as soon as the cable is plugged in, each Mac mounts the other's disks; unplugged, it unmounts them. No reboot, no commands, both Macs stay usable. It's the modern equivalent of Target Disk Mode — except it works in both directions.
| Target Disk Mode (Intel) | Share Disk (Apple silicon) | Cable + DiskBridge | |
|---|---|---|---|
| Reboot | Yes | Yes | No |
| Shared Mac stays usable | No | No | Yes |
| Direction | One way | One way | Both |
| Low‑level access (block cloning) | Yes | No | No |
| Speed | Cable | Cable | Cable |
| Automatic | No | No | Yes |
When Recovery is still the answer
Two cases: recovering data from a Mac whose macOS no longer boots (there, "Share Disk" in Recovery is the way), and cloning a volume block by block (use an external boot disk or a Time Machine backup instead). For everything else — exchanging, migrating, backing up, working on the other Mac's files — the cable is enough.
Step by step
- Install DiskBridge on both Macs (Mac App Store). The welcome window turns on File Sharing if needed.
- Link them with a Thunderbolt/USB4 cable (which one?).
- Enter the password of your account on the other Mac once. The disks appear in the Finder.
Get DiskBridge — free 14‑day trial, then a one‑time US$4.99.
Get DiskBridge on the Mac App Store
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.
- Migrating to a New Mac over a Cable: Migration Assistant or Manual Copy?
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