How to Boot a Mac in Target Disk Mode
Target Disk Mode is a very handy feature available to use with Mac’s that have Firewire or Thunderbolt ports, and it allows you to use one Mac as an external drive on another host machine. This makes troubleshooting, installations, large file transfers, and critical backups extremely easy and very fast.
How to use Firewire or Thunderbolt Target Disk mode
* First, be sure both Mac’s have Firewire or TB ports and that you have a Firewire or Thunderbolt cable
* Turn off the ‘target’ Mac (the one who’s drive you want to show up on the host)
* Now connect both Mac’s to each other with the Firewire or Thunderbolt cable
* Boot the target Mac while holding down the ‘T’ key until you see a Firewire icon
* In a few moments, the target Mac’s hard drive should appear on the host Mac’s desktop and you can access it like any other external drive
* When you are finished, safely eject the target Mac as if it’s any other disk
I use Target Disk Mode constantly, so it’s a good thing Firewire was replaced with Thunderbolt as a high speed data connection newer Mac rather than removing the Target disk feature completely. For the record, you can’t use Target Disk Mode with USB (at least for now).
I am really annoyed that you can’t do this with USB
What is the most important use of this mode?
Don’t laugh- I have a PowerMac G4 (it’s outlived 4 other Macs! and I just can’t get rid of it yet.) I want to ditch the monitor and have the HD show up on my new iMac. It looks like a monitor has to be connected or it won’t turn on. Any suggestions?
(They’re connected via firewire cable but it didn’t show up when I restarted my iMac even though it’s plugged in and *should* have power. )
Just in case you never found a solution to this did you try to just put a dummy plug in the monitor port?
pork
I am really offended why I can’t boot a mini with any of my laptop macs without adding an external keyboard and display (which I do not have at hand).
Thought Apple was all about friendly UIs …
[...] a recovery Lion partition, or connecting another Mac (via Firewire or Thunderbolt) and booting into target disk mode. This wasn’t an option for me as I didn’t have a recovery Lion USB device or a Firewire [...]