Okay all, I think I messed up really big time.

Was so excited and delighted today to see my brand spanking new MacBook Air arrive (running Catalina). Everything was wokring great; I started Migration Assistant to get it migrating over from my old computer and, after a little while for the preliminaries, it said it was going to be 6.5 hours. So I thought let's not do this right now, so I can still use the old computer, and cancelled it.

That was my first mistake.

It wouldn't let me go back to the original state of Migration Assistant; the users were already on the new computer. Okay, fine, I have to go into Utilities to find Migration Assistant on the new computer. But then when Migration Assistant did start up again, it would keep freezing in the early stages, stalled and not progressing - never even got to the part where it estimated time remaining. It did this in multiple ways, whether I was connected through WiFi or Ethernet, direct from the old Mac or through my Time Capsule.

So I figured I wanted to start clean. And this appears to be where I made the REALLY big mistake. I thought "well, I'll just wipe the data so I can start clean, right?" I tried to followed instructions for a factory reset: went into Recovery Mode (cmd-R), entered Disk Utility, deleted the Macintosh HD-Data partition. I thought that what I was supposed to do next was delete the Macintosh HD partition too. But it wouldn't let me do that because it was in use. I also tried to reinstall the US, and it wouldn't let me do that either (also because it was in use). Okay, I thought, I'll just restart and see what happens.

And now my brand new $1800 computer is completely bricked.

The Apple logo appears, followed briefly by the start of the progress bar - and then I hear this whooshing sound, like ocean surf or a heavy breath, and it turns back off again... and then the Apple logo appears again and the same thing happened. Over and over on an endless cycle, just Apple and whoosh. I can sometimes get it to turn off by holding the power button, but turning it back on just gives me the endless cycle and whooshing again; I can't get into Recovery mode. In the old days I would have tried sticking a paper clip in or some other option for a hard reboot, but there's nowhere to do that.

Help! How can I get back to a brand-new computer with the old data smoothly migrated?

1 Answer 1


If you have a time machine backup of your old computer or can make one (buy or borrow a spare disk drive) you can recover using the backup in recovery mode. Follow this https://www.idownloadblog.com/2016/02/29/how-to-restore-mac-time-machine-recovery-mode/ for instructions.

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    No, I cannot! That's the whole problem. As I noted above, I can't get into Recovery mode or any other mode, on the new computer. Nothing works on it. The old computer is fine. Commented Jun 24, 2020 at 12:22
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    OK. Maybe your recovery partition is damaged. How about internet recovery mode (OS is downloaded from Apple). macworld.co.uk/how-to/mac/recovery-mode-internet-3636668
    – mhaselup
    Commented Jun 24, 2020 at 12:30
  • Thanks, it did let me into Internet recovery mode - at least it started in Internet recovery mode, asking me to sign into the WiFi and so on. But now I'm back to a problem I had when I was in regular recovery mode before, where it says "Failed to unmount Macintosh HD because it is currently in use". Since I can't unmount it, I can't erase it; an attempted erase says it "couldn't be unmounted because it is in use by process 717 (kextcache)" "Couldn't unmount disk. : (-69888)". Nor will it let me reinstall macOS ("The target volume is part of incomplete system and can not be installed to.") Commented Jun 24, 2020 at 13:20
  • Try this osxdaily.com/2013/06/14/… You may be able to create a bootable recovery usb drive on your old mac. Alternatively as suggested you could force a unmount from the command line in recovery mode.
    – mhaselup
    Commented Jun 24, 2020 at 13:48
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    If you don't have another Mac, which you can connect and run Apple Configurator over the new Mac, then your best option is to make an appointment at an Apple Store.
    – benwiggy
    Commented Jul 11, 2023 at 10:02

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