Target disk mode is a type of boot mode in Mac that is used to transfer large files such as disk images, important backups etc. in a quick and efficient manner. This mode is also useful when you want to troubleshoot or access your Mac when it doesn’t boot.
How to use Target Disk Mode?
You will need 2 Mac systems and a FireWire cable to use Target Disk Mode. The Mac systems you plan to use for TDM needs to have a FireWire or Thunderbolt port.
One Mac acts as a Target, which as the name suggests is the system you want to access. It could be the non-booting Mac or the Mac with issues. The other Mac is the Host; this is the system that will be used to access the target, Mac.
Once you have both Mac’s set up, follow the steps below to use Target Disk Mode.
- Connect the two Mac’s
Connect the two Mac’s using FireWire or Thunderbolt cables. Also, make sure your Mac’s are plugged in to avoid running out of battery during the process.
- Start Target Disk Mode on target Mac
This can be done using 2 methods described as follows.
- Restart your Mac and press the ‘T’ key until you see a FireWire icon on the screen. T
- If your target Mac is turned ON, go to System Preferences > Startup Disk and select Target Disk Mode.
Once you have Target Mode turned ON, you are all set to transfer files.
- Transfer files
Your host Mac should now be able to detect the target, Mac. Now you can use this Mac as you would like any other external storage media. Open Finder to transfer any files you need and once that’s done, click on Eject to safely remove the connected Mac.
Why use Target Disk Mode?
Now that we know the basics of Target Disk Mode, let us understand when you can use this mode.
- To transfer files
Instead of using a USB flash drive or external hard drive as an intermediary between 2 Mac’s for transferring files, you can directly use a Mac to transfer files to another Mac. This is particularly helpful to transfer large files such as backups, disk images etc.
- Troubleshoot or access Mac that won’t boot
This is probably the most useful application of the Target Disk Mode. Sometimes you may face problems with booting your Mac (the common problem when you upgrade Mac). In such cases, you can use Target Disk Mode and access it through another Mac.
Once connected, you can perform troubleshooting on the target Mac or copy important files from the problematic Mac. However, if you’re still having trouble booting your Mac after using TDM, refer Mac wont boot after Sierra update. This link will provide you with some tips on recovering important files after OS upgrade.
While Target Disk Mode can be extremely useful when your Mac doesn’t boot or for file transfers, there are some drawbacks. For instance, you can’t use this mode if the target Mac’s drive is damaged or there are other hardware problems. But this is definitely a good option to consider when your Mac just has booting issues or screen trouble etc.