This is a quick image showing my cables and MacBooks.

I got a new MacBook Pro 13" with Touch Bar (A1706) and now I need to transfer all my data from my old 12" MacBook (A1534) to it. While Migration Assistant always generates errors over Wi-Fi, I see target disk mode could do the work.

From this official article by Apple it says:

Target disk mode on MacBook Pro with Thunderbolt 3 (USB-C) ports

You can use target disk mode to transfer data between MacBook Pro models with Thunderbolt 3 and other Mac computers.

To use target disk mode between a MacBook Pro with Thunderbolt 3 and another Mac notebook's USB-C port, connect the two computers with a USB-C cable such as the Belkin 3.1 USB-C to USB-C Cable.

So I got this Belkin 3.1 cable. However, when I restart the 12" MacBook into target disk mode and connect it to my 13" MacBook Pro when Migration Assistant is searching for the source, nothing happens.

Before this I actually accidentally got a Thunderbolt 3 cable to try, and nothing happened either.

So even the official post is not telling the right thing? Or where did I get it wrong? Which cable should I get to complete the job? I'm so confused right now.

  • I don't understand the reason why somebody would downvote this question. I searched everywhere and tried almost every method I can find
    – Hang Chen
    Nov 28, 2017 at 12:31
  • 1
    Have you tried booting the new one AFTER the 12" is already in target disc mode? Is the user name and password the same on both? I did this between an Imac (with a broken display) and my macbook pro - worked fine.
    – Solar Mike
    Nov 28, 2017 at 14:07
  • 1
    If you have a Time Machine backup, that could work too using an external hard drive.
    – bjbk
    Nov 28, 2017 at 14:10
  • @SolarMike Yes I tried booting the new one after the 12" enters target disk mode, but the new MacBook Pro doesn't have an user yet. It's quite new, without having set up a new user. I will try creating a user account and use the migration assistant app inside and give feedbacks later. Thanks for your reply!
    – Hang Chen
    Nov 28, 2017 at 14:21
  • @bjbk Thanks! If this still doesn't work I will try time machine. I downloaded carbon cloner and may try clone the disk for my last backup
    – Hang Chen
    Nov 28, 2017 at 14:22

2 Answers 2


After different kinds of attempts, I finally got it work by some sort of magic.

Short answer: USBC 3.1 cable does work, but you have to first leave two MacBooks unconnected, and turn on each other separately. Leave the 12” MacBook stay there for several minutes, with or without power supply, then use the cable to connect. Wait about 5 minutes, the disk will show on desktop or in disk-utility app.

Here’s how I found it working if you are interested:

Although initially I could hear the charging sound from my old 12” MacBook when connecting it to my new MacBook Pro when 12” is on target disk mode, the disk never showed up on migration assistant, desktop or disk utility, for however long time I wait. Then I was thinking if the cable was the right cable, and that brought me to my original question. To troubleshoot the cable, I came up with another idea: I put the new MacBook Pro in target disk mode this time, and connected it my 12” MacBook, see if 12 inch can recognize the new cable. The reason I did this is because in my opinion, the new MacBook definitely can use this 3.1 cable, since it’s thunderbolt 3 port so it shoudn’t have downwards capability issue, but I am not sure if the USBC port on 12” could since it is still a USBC gen1 port and this cable is gen2.

To my surprise, about 2 minutes later the disk from my new MacBook showed up on my 12”, and I did a little file transfer successfully. So the cable is good, and there’s no reason it can’t be used reversely. I begin to make different attempts, by reversing the cable(although I know this shouldn’t be an issue for usb-c), and by booting each MacBook in different orders with cable connected or without.

Finally, it led me to the result I described in my short answer. And I tried 3 more time, all work. Booting with the cable already attached will not give you any result, at least in my case. I waited the whole night long and I still didn’t see it was mounted when I woke up this morning. So if are you experiencing this issue, definitely try booting the computers separately without cable connected, and then connect it. And most importantly, you may have to wait(plus, I actually found this method by accident as well. After so many failures I was calling an apple care representative for help, and she put me on hold to find the infomrmstion on whether this cable would work or not. While waiting for her reply about 5 minutes later, the disk showed up! So I recalled what I did, and that is in my short answer) for several minutes. I don’t know the reason, and this could be very tricky as you may think this would fail again. But be patient and follow the steps and you will be good!

Edit: I’m still keeping the thunderbolt 3 cable however, and I will try that with some updates later. I’m doing the migration now. Finger crossed!


You don't use migration assistant in Target disc mode. U simple look for the old mac, same as connecting an external HDD. When you connect you will be prompted for the password that you use to login to the old computer and walla you now have access to your old files which you can transfer to your new computer. Using a USBC to THUNDERBOLT 2 (Mini DP) cable is the fastest method of data transfer.

  • ...no, you can use Migration Assistant if you want. Additionally, the USB-C port on the 12" MacBook does not have Thunderbolt 3, and the 2017 MacBook Pro doesn't have Thunderbolt 2. A USB-C to USB-C cable is what's appropriate. OP seems to have this in order.
    – JMY1000
    Jun 25, 2018 at 2:40

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