Target Disk Mode allows you to share large files instantly between two Macs simply by connecting them via a Thunderbolt or FireWire cable. Moreover, in scenarios where a Mac does not mount well or no longer boots, Target Disk Mode can be leveraged to access the hard drive’s data.
Target Disk Mode for Troubleshooting Mac
Target Disk Mode provides quick file sharing between two Macs by making one Mac appear as an external hard drive on another working Mac. Before beginning, it is important that you get yourself abreast of terms ‘Target Mac’ and ‘Host Mac’. ‘Target Mac’ is the Mac which boots in ‘Target Disk Mode’ (being used as an external hard drive) and the ‘Host Mac’ is where you are copying your data to.
Target Disk Mode is a handy feature for quick transfer of large files from:
Old Mac to your new Mac
A Mac with the damaged screen, no display, broken screen etc.
For backing up important files before downgrading Mac OS
Things you’ll need for data retrieval or transfer:
Two Macs: You need two Macs i.e. target Mac and the host Mac
Connecting cables: One connecting cables (FireWire, Thunderbolt) to chain two Macs together
FileVault Encryption: Disable FileVault encryption before using Target Disk Mode
The FileVault encrypts the entire hard drive
Setting up The Hardware
Prior to file transfer, make sure that the target and the host Mac use the same port, for example, if the host Mac has Thunderbolt port, then the target Mac must also have a Thunderbolt port.
However, in a scenario where Macs have different ports, a Thunderbolt to FireWire adaptor will work. It is important to connect your systems with the correct cables.
Target Disk Mode
After establishing the connection using the appropriate cable, turn on the host Mac. If the target Mac is ON, go to System Preference, select Start-up Disk and click Target Disk Mode.
*Note: Click on the lock icon before clicking on Target Disk Mode
Restart the target Mac and wait till Thunderbolt/FireWire logo appears on the screen. If the target Mac is turned OFF, press and hold the ‘T’ key and then press the power button. Your target Mac will boot up with the Thunderbolt/FireWire icon.
Now that the target Mac is booted into Target Disk Mode, you can easily access all the files stored on it. So, let’s delve into different cases illustrating how Target Disk Mode is used:
CASE 1: Using the Host Mac as a Backup
As the target Mac appears as an external hard drive on the host Mac, you can drag and drop files from the target Mac to the host. To transfer files, go to Finder and find the target Mac listed as an external drive, select required files and transfer them. This one-step file transfer feature is useful for transferring large files such as video editors, HD videos at a high transfer rate and when you’re done, simply eject the target Mac like any other external hard drive.
CASE 2: Boot the Target Mac OS on the Host
If your Mac does not boot up, you can use Target Disk Mode to boot it. The target Mac shows up as a bootable drive on the host Mac. To boot your target Mac, press the power button on the host Mac and press and hold the Option key. After a few seconds, the host Mac will boot up and display all the connected bootable volumes. Select the required volume to boot, and after a few seconds, the host Mac will run the target Mac’s OS. However, there are a few points that need to be considered prior to booting:
Make sure that the two Macs support same internal hardware as it could be possible that one Mac doesn’t have the required drivers needed for the hardware
The OS should be same on the two Macs. Ensure that the target Mac is running OS version equal to or greater than the host Mac as older version of OS may not support the hardware configuration
CASE 3: Restore Data from the Target Mac
Through Target Disk Mode you can restore data from problematic Macs. You can back up or restore crucial files from the target Mac and save them on the host Mac. This is one of the easiest and fastest ways of restoring all your files from the non-booting hard drives. You can access all files as long as the target Mac is recognized by the host Mac. You can even format, partition and repair volumes of the target Mac on the host via Disk Utility.
Also, in scenarios wherein the target Mac is listed as unmounted, you can run a data recovery software on the host Mac for retrieving your files. Stellar Data Recovery for Mac software recovers data from the unmounted drive. You can recover all your data from the target Mac in following simple steps–
Run the software on the host Mac
Choose file types you want to restore from unmounted drive
Select the target Mac hard drive or Scan the target Mac
Preview the files
Save the files on the host Mac
Target Disk Mode is indeed an incredible Mac built-in utility which allows for quick and simple files transfer and also lets you repair the target Mac’s hard drive as well. As a last minute tip, back up all your crucial data.
Arpana is a passionate technical writer for MacOS, fitness-freak and a traveler. She loves to explore new places. Her MacBook Pro 2017 is her best companion. Arpana insists on backing up a Mac timely, however, she has covered her MacBook with a file recovery tool.