Let me start by saying I love my MacBook Pro Retina 15″, it’s a beautiful machine.  Yes, I am an Apple fanboy, but I’ve owned Dells, HPs and Toshibas in the past as well.  I can honestly say I’ve been on both sides of the fence, and for me, the MacBook Pro is the superior machine.  For the first time in 5 years using a MacBook as my primary laptop for work and play, I’ve run into some weird issues that have really cramped my ability to use the machine.  For some reason, my trackpad is not wanting to left click anything.  I can use the  trackpad to right click, move the cursor around and navigate, but it just won’t left click.  Not only that, but I’ve also noticed multiple apps that are freezing or hanging on boot, even after removing them from start up.  Yes, before you ask, I have taken it to the Genius Bar at my local Apple Store, and after running diagnostics on the trackpad (which passed) they couldn’t even figure out what was going on with it.

“Here target disk mode comes to save the day…”

So here I find myself with an unusable laptop, so I resort to calling my company’s help desk (it’s a company laptop).  After telling them, “yes, I did take it to Apple already” they decided it would be best to re-image the machine, which requires me to send it to the help desk team in Colorado.  Unfortunately, re-imaging a laptop also means losing everything you have stored on it, so I had to find a way to get my docs/pics/music off the computer and onto my kids MacBook Pro (MBP).  This is where Target Disk Mode steps in to save the day.  After a quick Amazon Prime purchase of a 6′ Thunderbolt to Thunderbolt cable, I’m able to get started moving my stuff off my broken MBP and onto my kids MBP, temporarily until they send back my newly re-imaged MBP.

So what is Target Disk Mode and what will it actually do for me?  Target Disk Mode will allow you to boot your Mac up and have it appear to another Mac as an external disk drive.  One machine will act as the host and the other will act as an external disk drive.  Booting into target disk mode allows  you to manage large file transfers, make backups faster, and troubleshooting easier.  Your pre-requisites to having this work are 1) making sure both Macs have Thunderbolt ports and 2) both Macs are actually able to boot up.  If you don’t have Thunderbolt ports, a converter might work but the speed/efficiency of the transfer(s) might be degraded.

How to use Target Disk Mode

Below I’ve laid out the step by step process of using target disk mode.  If you ever find yourself in my situation, this is a good utility to use in order to save what you most likely don’t have backed up.

  1. Make sure your ‘target’ Mac, in my case the one that’s having issues, is powered off.
  2. Connect both Thunderbolt ports together via a Thunderbolt to Thunderbolt cable.
  3. Boot up your ‘target’ Mac while holding down the ‘T’ key until you see the Thunderbolt or disk icon appear on your screen.  This will let you know that target disk mode is working.
  4. After the ‘target’ Mac is done booting up, a disk icon should appear on your other Mac’s desktop, once you see this icon, you can now pull items off the ‘target’ Mac’s hard drive, or drag things onto it.
  5. Being a good administrator/user… when you are done with target disk mode, you can simply drag the disk icon to the trash in order to safely eject it.  After ejecting it, your ‘target’ Mac can now be used as usual, unless you are in my situation and you simply pulled all your data off so you can re-image the machine… 🙁

As a side note, FileVault encryption is enabled by default in Macs today.  FileVault will keep you from accessing your encrypted home directories via Target Disk Mode.  If you need access to those home directories while in Target Disk Mode you will first need to go to the ‘target’ Mac and navigate to System Preferences and select Security & Privacy, then select FileVault and turn it off.  I would suggest only turning this feature off temporarily, so make you set yourself a reminder to enable it again after you are done with Target Disk Mode.

Greg W Stuart
Greg is the owner and editor of vDestination.com. He's been a VMware vExpert every year since 2011. Greg enjoys spending time with his wife and 3 kids. He works as a Sr. Consultant at VMware and resides in Northern Virginia, 15 minutes west of Washington DC.

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