Target Disk Mode is a Mac-exclusive feature that plays an important role in data recovery and file transfers. In this boot mode, the Mac’s firmware allows its storage disk to act as an external storage device without having to load the MacOS.
You can connect two Macs or a Mac to a Windows PC using Thunderbolt or FireWire cables to perform the file recovery operation. Connecting from Mac to Mac is fairly simple, but you will need software to access your Mac on a Windows PC.
Target Disk Mode can be used for a variety of purposes:
- Copy files from one Mac to another without setting up file sharing or creating a local network.
- Troubleshoot the hard drive of a Mac that doesn’t boot from the desktop.
- Use an optical drive on your Mac in “Target Disk” mode as if it were connected to your Mac.
- Use the Mac OS operating system on the Mac in Target Disk mode to boot a second Mac.
As you can see, Target Disk mode can be quite versatile and can solve a problem accessing or sharing data from one Mac to another Mac.
Two things can make it difficult to put a Mac in target disk mode: FileVault and a firmware password. Both are easy to bypass:
If the Mac is encrypted with FileVault, press and hold the T key at startup as usual, but then enter the administrator password for that Mac to complete the transition to target disk mode.
If the Mac has a firmware password, press the Option key on startup and enter the firmware password when prompted. Then press the T key to continue booting in target disc mode.
In addition, the Apple USB-C charging cable included with the power adapter for MacBook, MacBook Air, and MacBook Pro models does not support target drive mode. If you want to use this cable, you will need to purchase a genuine Thunderbolt or USB-C cable.
Despite these small caveats, target drive mode is one of the little-known innovations that has made Macs easier to use for decades, and it’s a good idea to remember it if you need to move a lot of data between computers.
Disable Firmware Password
By default, your Mac boots from its built-in hard drive, but a boot drive can be any storage device that contains an operating system compatible with your Macbook. If the firmware password is enabled on your Macbook, you won’t be able to activate the destination drive mode from a cold boot. Therefore, use the Boot Security Utility to ensure that the firmware password protection is disabled.
Using an external hard drive as the target Mac
Target hard drive mode allows direct file transfers from your target Mac to your host Mac as if your target Mac was simply an external hard drive connected to your host Mac. In addition to using another Mac to boot a non-reactive system in target disk mode, a working system can also run on an external drive. If your Mac has a software problem, booting from an external drive usually works. So follow the steps below to connect the external drive to your host Mac.
Conclusion
Special startup modes on Macs require the system to detect the keys pressed before the firmware passes control to the operating system. This feature is available immediately when the system startup chime sounds, which is also the case when Bluetooth keyboard controllers are activated. This means that with wireless keyboards, you may have problems activating the target disk mode because you must press and hold the T key immediately when the system startup chime sounds, unlike before. So if you’re having trouble switching your system to target disk mode, try using a USB keyboard and holding down the T key from the moment you turn on your Mac.