How to use and troubleshoot FireWire target disk mode

Learn how to use and troubleshoot FireWire target disk mode.

This article has been archived and is no longer updated by Apple.

FireWire target disk mode allows a Macintosh computer with a FireWire port (the target computer) to be used as an external hard disk connected to another computer (the host). Once a target computer is started up as a FireWire hard disk and is available to the host computer, you can copy files to or from that volume.

Host computer requirements

Host computers must meet these requirements:

  • Built-in FireWire port or a FireWire port on a PC card
  • FireWire 2.3.3 or later
  • Mac OS 8.6 or later

Target computers

These models can be used as target computers:

  • iMac (Slot Loading) with Firmware version 2.4 or later
  • iMac (Summer 2000) and all models introduced after July 2000
  • eMac (all models)
  • Mac mini (all models)
  • Power Mac G4 (AGP Graphics) with ATA drive
  • Power Mac G4 Cube
  • Power Mac G4 (Gigabit Ethernet) and all models introduced after July 2000
  • Power Mac G5 (all models)
  • Mac Pro (all models)
  • iBook (FireWire) and all models introduced after September 2000
  • PowerBook G3 (FireWire)
  • PowerBook G4 (all models)
  • MacBook Pro (all models)
  • MacBook models introduced before October 2008

Read more about FireWire Ports and Specifications.

Note: FireWire Target Disk Mode works on internal PATA or SATA drives only. Target Disk Mode only connects to the master PATA drive on the Ultra ATA bus. It will not connect to Slave ATA, ATAPI, or SCSI drives.

Before attempting FireWire target disk mode, check these items:

  • Make sure your software and firmware are up to date.
  • Disconnect all other FireWire devices from both computers before you use FireWire target disk mode. Do not connect any FireWire devices until after you have disconnected the two computers from each other or have stopped using target disk mode.
  • If "Open Firmware Password" has been enabled the computer will not go into Target Disk mode. More information on Open Firmware Password is available in the "What to do if your Mac doesn't enter FireWire Target Disk Mode" section of this article.
  • If you will be transferring FileVault-protected home directories (Mac OS X v10.3 or later only), log in as the FileVault-protected user and temporarily turn off FileVault. After transferring home directory contents to the target computer, enable FileVault protection again if you like.

To use FireWire target disk mode

  1. Make sure that the target computer is turned off.
  2. If you are using an Apple portable computer such as a PowerBook or MacBook as the target computer, plug in its AC power adapter.
  3. Use a FireWire cable to connect the target computer to a host computer. The host computer can be powered on.
  4. Start up the target computer and immediately press and hold down the T key until the FireWire icon appears. The hard disk of the target computer should become available to the host computer and will likely appear on desktop. (If the target computer is running Mac OS X v10.4 Tiger, you can also open System Preferences, choose Startup Disk, and click Target Disk Mode. Restart the computer and it will start up in Target Disk Mode.)
  5. When you are finished copying files, locate the target computer's hard disk icon on the desktop of the host computer and drag it to the Trash or choose Eject (or Put Away) from the File menu.
  6. Press the target computer's power button to turn it off.
  7. Unplug the FireWire cable.

Tips for using target disk mode with Intel-based Mac computers

If you attempt to mount an Intel-based Mac in target disk mode on a Macintosh running Mac OS X v10.3.9 or earlier, you'll see an alert message. For more information, see Intel-based Macs: "You have inserted a disk containing no volumes that Mac OS X can read" alert message.

If your Intel-based Mac is becoming unresponsive while in Target Disk Mode, refer to Intel-based Mac may become unresponsive in target disk mode.

What to do if your Mac doesn't enter FireWire target disk mode

If your computer does not enter FireWire target disk mode when you hold down the T key at startup and instead starts up into Mac OS, try these steps:

  1. Make sure the FireWire cable is good, and check the connection. 
  2. Make sure no other FireWire devices are connected.
  3. Make sure you are starting up the computer while pressing and holding down the T key.
  4. Check the keyboard connection. Make sure the keyboard is connected directly to the computer and not through a display or hub. Whenever possible use an Apple wired or wireless keyboard. 
  5. Make sure that Open Firmware Password has not been enabled on this computer. Depending your OS version you may need to download the Open Firmware Password software. For more information on Open Firmware passwords, review Setting up firmware password protection in Mac OS X.
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