1

Hardware

iMac, 2019
3 GHz 6-Core Intel Core i5
Ventura 13.6.3

MacBook Air, 2020
Apple M1
Sonoma 14.2.1

Thunderbolt cable (edit: actually, charging cable. My mistake.)

Problem

I want the iMac in Target Disk Mode so that I can see it from the MacBook. I have followed the instructions outlined in Transfer files between two Mac computers using target disk mode (support.apple.com) to no avail. The iMac boots in Target Disk Mode (shows lightning and USB icons), but there's no indication my MacBook sees it (e.g., no disk icon on the desktop).

Can a MacBook Air and iMac be connected in this way, and, if yes, how?

Notes

  1. The cable is working insofar as the MacBook is drawing power from the iMac.
  2. No other devices are connected to either computer.
  3. Each computer has two thunderbolt ports, but changing ports has no effect.

3 Answers 3

1

Transferring files from an intel mac in TDM to anything with a usb port should just work, including an Apple Silicon Mac.

The cable is working insofar as the MacBook is drawing power from the iMac.

This is not enough. Are you perhaps using the charging cable that came with the Apple Silicon Mac? Because that will not be enough. You need a firewire or thunderbolt cable, which is quite expensive.

With the correct cable, and with the intel Mac set to TDM, you should be able to access your files. Good luck!

4
  • "I've got ninety-nine cables, but a double-ended USB-3 ain't one." "For want of a double-ended USB-C cable, the business was lost."
    – Aaron
    Commented Mar 28 at 19:44
  • Remarkable what happens when you have the right cable.
    – Aaron
    Commented Mar 29 at 3:45
  • USB C cables are a nightmare for end users. It is unfortunate that cables that support the whole spec can cost 10x cables that just charge your mac, and even 100x than cables that barely - but still - work. I am glad you solved it @Aaron Commented Mar 29 at 7:40
  • FWIW, I was able to get a TB3 cable on the relative cheap (33 USD), and it did the job perfectly.
    – Aaron
    Commented Mar 29 at 17:25
2

You cannot use Target Disk Mode (TDM) between Mac computers of differing architectures.

TDM was a mode that allowed you to boot your Mac into this mode so the internal drives of the target machine would appear as external drives to the boot Mac. You can hold the T key while booting (from a powered off state) or select the startup disk from System Preferences.

With Silicon based Mac, you’re not booting into that special mode but rather, you’re creating a network share of the entire disk. This is why it can be done over Thunderbolt or USB-C whereas the original TDM required Firewire or Thunderbolt.

See Transfer files between a Mac with Apple silicon and another Mac for full instructions and details. But, to put this succinctly, you’re just creating a peer-to-peer network between two computers and sharing the whole disk rather than some files/folders.

(IMO) Apple should state this clearly, rather than obfuscate it by burying the links two pages deep.

4
  • I'm just trying to get my MacBook to read and write files from the iMac. It seems like something that should be simple to do, but so far, I haven't found it.
    – Aaron
    Commented Mar 28 at 6:54
  • Use a cloud service
    – Allan
    Commented Mar 28 at 14:00
  • The iMac is offline for the next few weeks at least, which is the ultimate source of the problem.
    – Aaron
    Commented Mar 28 at 14:38
  • 1
    I am not sure why OP accepted this answer; for what I understand from the original question, OP wants to set the intel mac into TDM and hook it up to the M1 mac. This should just work, and when I upgraded my mac from intel to M2 I did precisely this and it did work. Commented Mar 28 at 16:20
1

I think you need to look at a different support page:

Transfer files between a Mac with Apple silicon and another Mac

Apple Silicon Macs like your M1 MacBook act as SMB file servers when in target mode, not external drives.

2
  • It’s the iMac I want as the file server.
    – Aaron
    Commented Mar 28 at 14:31
  • You can still transfer files between the two computers if the MacBook Air is the server.
    – Mr. Mel
    Commented Mar 29 at 16:08

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