What is target disk mode and how to use it

Mac target disk mode is one of those features of the Mac that, if you use it regularly, you’ll find indispensable, and if you have never used it, you may not even realize it exists. It’s one of many ways that you can share files from one Mac to another. Unlike most of the others, target disk mode needs a physical connection between two Macs. In this article, we’ll explain exactly what target disk mode is and how to use it.

What is target disk mode?

Target disk mode on Mac is a feature of macOS that allows one Mac to act as a storage device for another. When you connect one Mac to another and boot it in target disk mode, it shows up in the Finder of the other Mac as if it were a storage volume like a hard drive, SSD, or USB memory stick.

When it was first introduced, the Macs had to be connected using a FireWire cable, but since Apple stopped using FireWire on Macs, you can now use either USB or Thunderbolt cables. However, if one of the Macs you are connecting is running macOS 11 or later, you must use Thunderbolt.

You can connect either Apple silicon or Intel-based Macs or one of each. On Macs with Apple silicon, the feature is called Mac sharing mode. If you want to connect an Intel-based Mac to a Mac with Apple silicon, the latter has to be the target disk.

Before you start

If you plan to copy all the data from one Mac to another using target disk mode, it’s a good idea to get rid of all the junk first. You don’t want to copy across lots of junk files, like temporary files, caches, and languages you don’t use to the other Mac. The easiest way to get rid of all those junk files is to use the System Junk module in CleanMyMac X. It scans your Mac looking for junk files, and when it’s done, you can either review what it has found or delete them all with one click. CleanMyMac X also has the Large & Old Files module that identifies the largest and oldest files on your Mac and makes it easy to see which ones you can get rid of to free up the most space. You can download CleanMyMac X for free here and try it for yourself.

CleanMyMac X - System junk scan complete

How to use target disk mode with two Intel-based Macs

  1. Connect the two Macs together using either a USB, USB-C, or Thunderbolt cable. If either of the Macs is running macOS 11 Big Sur or later, you will need to use a Thunderbolt cable.
  2. If the Mac you want to use as the target disk is powered on, go to step 3. If it’s off, go to step 5.
  3. Click on the Apple menu, choose System Settings, then General.
  4. Choose Startup Disk, then Restart in target disk mode.
  5. Press and hold the T key, then press the power button to boot the Mac.
  6. When you’re finished transferring files, eject the target disk from the other Mac in the Finder by hovering over it with the pointer in a Finder window sidebar and clicking the eject icon.
  7. Press the power button to turn off the Mac you used as a target disk, and disconnect them.

How to use target disk mode on a Mac with Apple silicon

If you want to connect a Mac with Apple silicon to an Intel-based Mac, you need to use the former as the target disk.

  1. Connect the two Macs together using a USB, USB-C, or Thunderbolt cable (again, if one of the Macs is running Big Sur or later, you must use a Thunderbolt cable).
  2. If the Mac you want to use as the target disk is powered on, shut it down.
  3. Press and hold the power button on the target disk until you see ‘Loading Startup Options’ on the screen.
  4. Click Options, then Continue.
  5. Choose the disk you want to use as a startup disk, then Continue.
  6. Sign in with your admin account if requested.
  7. The Mac will boot into recovery mode, and you will see macOS Utilities.
  8. Click the Utilities menu and choose Share Disk.
  9. Choose the volume you want to share and click Start Sharing.
  10. On the other Mac, open a new Finder Window.
  11. Look in the sidebar under Locations and click Network.
  12. Double-click the Mac that is connected and you want to use as the target disk.
  13. Click Connect As, then Guest, then click Connect.
  14. When you have finished transferring files, click Stop Sharing on the target disk.
System Preferences - General information

Alternatives to target disk mode

If you can’t, or don’t want to, use target disk mode but still need to transfer data from one Mac to another, there are lots of options.

  1. File sharing. Go to System Settings > General > Sharing and turn on File Sharing on the Mac you want to connect to. It will display an IP address. Make sure both Macs are on the same network and go to Finder > Go > Connect to Server on the other Mac and paste or type the address that was shown when you turn on File sharing. You will then see the other Mac in the Network section in Finder and be able to copy files to and from it.
  2. An intermediate disk. This is probably the easiest way of all if you have a spare external hard drive or SSD. Connect it to one Mac, copy the data you need, then connect it to the other Mac and copy the data off.
  3. Cloud storage. Got an iCloud or Google Drive account? Copy the files you need from one Mac into iCloud Drive or Google Drive and then, when it’s finished syncing, copy it to the other Mac.

MacBook target disk mode — or Mac sharing mode as it’s called on Macs with Apple silicon — is a feature that allows you to connect two Macs together with a USB, USB-C, or Thunderbolt cable and transfer data between them. Follow the steps above to use it on your Mac.

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