Target Disk Mode– MacBook does not mount in iMac desktop

Question

Target Disk Mode– MacBook does not mount in iMac desktop

I have a 2015 MacBook and a USB-A-USB-C cable marked "SS". In November 2015 I could start my MacBook in TDM and connect it to my 2013 iMac and see it mount on the desktop. I could then synchronise some of the folders (using Folders Synchroniser) and have up-to-date information on my MacBook. Both computers are running El Capitan.

But about 3 months ago this system stopped working. My MacBook's mounting on the iMac desktop became sporadic and now never happens. I've tried different cables, connected to different USB ports (the back of the iMac, the keyboard of the iMac and a Lightning to USB dock (Belkin)), but no joy.

Has the firmware of either computer been updated? Has El Capitan stopped this very useful feature from working?

Any ideas, anyone?

Chris

Posted on Aug 28, 2016 4:02 AM

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Answer 1

Apr 19, 2017 1:23 AM in response to Christopher Barker1

I've been using a USB-A / USB-C cable to access the hard drive of a MacBook "Core M" 1.2 12" (Early 2015) in target disk mode. The host is a MacBook Pro MD102LL/A. Sometimes the little MacBook mounts, sometimes not. The work-around is as follows: If it's not mounting power down the 2015 MacBook, plug it in using the original Apple power adaptor, wait for the battery symbol, and then restart it holding down the T key. Once you see the USB symbol on the screen simply unplug the power adaptor and then quickly plug in the USB-A / USB-C cable to access the drive.

As a side note, the 2015 MacBook appears to charge via the USB cable while in target disk mode anyway.

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Answer 2

RIFerrarr

Level 4

1,181 points

Aug 28, 2016 7:51 AM in response to Christopher Barker1

As a work around, there are other ways to sync folders across devices.

iCloud Drive, DropBox, Box, OneDrive, Google Drive. These will all do what you are doing.

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Answer 3

Aug 28, 2016 7:53 AM in response to RIFerrarr

Thanks for that reply. I use iCloud, Box, Dropbox and Sync for many of my files, but there are some which I don't want to spread over the Cloud.

As a matter of interest, Google Drive seems to have speeded up in the last couple of years; for ages it was much slower than DropBox, but now they all seem to work as well as each other.

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Answer 4

RIFerrarr

Level 4

1,181 points

Aug 28, 2016 8:04 AM in response to Christopher Barker1

As another type of work around, you can connect to each computer and set up File Sharing for whichever computer has the documents you need to share. You have a Public folder in your User folder. You can share what is in there.

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Answer 5

Aug 28, 2016 8:04 AM in response to RIFerrarr

Hmmm! I've never used the Public Folder. Thanks!

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Answer 6

Oct 1, 2016 2:24 PM in response to Christopher Barker1

I had this problem too. I turned off my macbook, plugged it in for secure power, then restarted TargetDM. Then the Macbook mounted as expected. 🙂

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Answer 7

Oct 2, 2016 9:23 AM in response to gregfromoakland

Thanks for your help. I assume that you mean that you plugged in the external power to a hub and connected the USB data cable to the hub as well as the power cable. I've tried that and there is no change: the MacBook does not appear on the iMac's Finder.

Chris

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