myles_sica

Q: Target disk boot Macbook USB-C to iMac

I am trying to boot my Macbook through a USB-C to USB-A 3.1 cable on my iMac to take advantage of the PCI-e storage in the macbook and quad core i7 in the iMac but I can't seem to get the iMac to find my Macbook as a bootable drive, although it does show up as an external disk on the iMac's desktop when booted into os x. Has anyone successfully done this? Apple has no answers.

MacBook (Retina, 12-inch, Early 2015), OS X Yosemite (10.10.4)

Posted on Aug 13, 2015 2:36 PM

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Q: Target disk boot Macbook USB-C to iMac

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  • by Kappy,

    Kappy Kappy Aug 13, 2015 2:45 PM in response to myles_sica
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    Aug 13, 2015 2:45 PM in response to myles_sica

    If it shows up as an external disk it's still usable. Why do you need to boot from the MacBook from the iMac? To do that you simply boot the MacBook normally while booting the iMac into Target Disk Mode. If you want the iMac to be able to use the flash drive in the MacBook, then boot the iMac normally and boot the MacBook into Target Disk Mode. Of course the two must be connected to one another. I'm not sure you can do that via USB.

  • by Kappy,

    Kappy Kappy Aug 13, 2015 2:47 PM in response to myles_sica
    Level 10 (271,101 points)
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    Aug 13, 2015 2:47 PM in response to myles_sica

    If you want a faster boot on your iMac, then get an external enclosure, install an SSD in it, and connect it to your iMac. Get an enclosure that supports either Thunderbolt or USB 3.0. See OWC for options.

  • by myles_sica,

    myles_sica myles_sica Aug 13, 2015 3:31 PM in response to Kappy
    Level 1 (0 points)
    Aug 13, 2015 3:31 PM in response to Kappy

    I edit videos and want to be able to take my main "Macintosh HD" (With application keys) wherever I go, but when it comes time to render effects, I want to be able to use either my mac pro or iMac to boot the Macintosh HD.

  • by Kappy,

    Kappy Kappy Aug 13, 2015 3:57 PM in response to myles_sica
    Level 10 (271,101 points)
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    Aug 13, 2015 3:57 PM in response to myles_sica

    Then why not just copy those files to your desktop computer over your local network when the need to render arrives.

  • by myles_sica,

    myles_sica myles_sica Aug 13, 2015 4:42 PM in response to Kappy
    Level 1 (0 points)
    Aug 13, 2015 4:42 PM in response to Kappy

    I have very expensive programs with only one product key that I would like to launch on my other machine and my work machine. I'm not looking for a work around, I was under the impression that I would be able to boot this Macbook through USB and that's exactly what I want to do.

  • by Kappy,

    Kappy Kappy Aug 13, 2015 5:23 PM in response to myles_sica
    Level 10 (271,101 points)
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    Aug 13, 2015 5:23 PM in response to myles_sica

    Then, I think what you need to do is:

     

    Boot the iMac into Target Disk Mode.

    Boot the MacBook normally.

     

    The iMac will appear on the MacBook's desktop. The MacBook is able to access the files and apps on the iMac.

     

    The reverse is to boot the MacBook into Target Disk Mode and boot the iMac normally. The MacBook will appear on the iMac's Desktop.

     

    Pick the one you need when you need it.

  • by myles_sica,

    myles_sica myles_sica Aug 13, 2015 5:31 PM in response to Kappy
    Level 1 (0 points)
    Aug 13, 2015 5:31 PM in response to Kappy

    I don't think you understand the issue, I can see the macbook as an external drive when plugged into the iMac. I want to boot the OS of my macbook to my iMac, like I've done hundreds of time before with Thunderbolt, Ethernet and Firewire. Apple said this should be possible but they do not make a native cable and can't tell me why this won't work. My macbook boots into target disk just fine and it even charges, but the only way to transfer data is to use it as an external usb and if you've ever worked with video files, you know what a pain it is when they are no longer linked.

  • by Lanny,

    Lanny Lanny Aug 13, 2015 9:31 PM in response to myles_sica
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    Aug 13, 2015 9:31 PM in response to myles_sica

    It doesn't work the same way with the new MacBook. You can manually transfer data with target disk mode, but Migration Assistant doesn't work with it.

     

    but I can't seem to get the iMac to find my Macbook as a bootable drive,

    It is not going to show up as a bootable drive to another Mac.

     

    https://support.apple.com/en-us/HT204360

     

    Your MacBook with USB-C port supports USB target disk mode. You can enable target disk mode and use the following USB-C cables to transfer data. These cables are not currently available from Apple.

    • USB 3.0 or USB 3.1 USB-A to USB-C Cable: Use this cable to manually transfer data from any Mac notebook with USB-A port(s) to your MacBook with USB-C port. This cable cannot be used to migrate data using the Setup Assistant or Migration Assistant application.
    • USB 3.0 or USB 3.1 USB-C Cable (USB-C to USB-C): Use this cable to migrate data from any MacBook with a USB-C port to another MacBook with USB-C port using the Setup Assistant or Migration Assistant application.

    To enable target disk mode, hold down the T button on your keyboard while starting your MacBook. Then connect either of the USB-C cables described above. The USB-C Charge Cable (2m) supplied with your MacBook doesn't support target disk mode.

  • by myles_sica,

    myles_sica myles_sica Aug 14, 2015 9:46 AM in response to Lanny
    Level 1 (0 points)
    Aug 14, 2015 9:46 AM in response to Lanny

    why would my mac not appear as a bootable drive? This feature should be fully supported and I am not in any way shape or form trying to use migration assistant or setup assistant rather, essentially use my Macbook as an external boot drive (been able to do it for years with external USB drives on macs). I have read the HT204360 a hundred times and I appreciate the response but none of what you highlighted pertains to my specific question. I already have a USB-C to USB-A cable which charges and allows data sync with my computer, I was even able to use migration assistant without any issues even though it's not supported right now according to HT204360.

  • by Lanny,

    Lanny Lanny Aug 14, 2015 10:07 AM in response to myles_sica
    Level 5 (7,952 points)
    Desktops
    Aug 14, 2015 10:07 AM in response to myles_sica
    why would my mac not appear as a bootable drive?

    Because that is a feature that uses a Firewire Target Disc mode, not a USB connection.

  • by myles_sica,

    myles_sica myles_sica Aug 14, 2015 11:31 AM in response to myles_sica
    Level 1 (0 points)
    Aug 14, 2015 11:31 AM in response to myles_sica

    No, this is not a firewire or thunderbolt specific function. When you hold down T during startup, it puts the Macbook into Target Disk mode, since the drive on the Macbook is formatted to be a bootable drive, you should be able to boot the Macbook through a USB connection, just as if the SSD were an external drive.

  • by Lanny,Helpful

    Lanny Lanny Aug 14, 2015 12:45 PM in response to myles_sica
    Level 5 (7,952 points)
    Desktops
    Aug 14, 2015 12:45 PM in response to myles_sica

    The only way that a Mac can be used as if it were an bootable external drive is by putting it Target Disk mode with a Firewire connection.

  • by myles_sica,

    myles_sica myles_sica Aug 14, 2015 12:49 PM in response to Lanny
    Level 1 (0 points)
    Aug 14, 2015 12:49 PM in response to Lanny

    *previously. With any other mac you can't use USB-C.. therefore you wouldn't be able to use your mac as an external USB drive, but the Macbook does have these capabilities; somewhere the piece of code was not written to recognize this type of connection on legacy computers but it is indeed theoretically possible.

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