I was trying configure my Mac to dual boot Ubuntu and macOS. In the process, I somehow managed to make Macintosh HD unbootable (is that a word?). I was able to boot Ubuntu just fine. I had just recently created a Time Machine backup so I tried to restore it.

  1. I booted up while holding the Option key
  2. Selected my backup disk (this is the only disk that was visible)
  3. Erased APPLE SSD and created a new Macintosh HD partition using the APFS (case-sensitive) format and GUID partition map.
  4. Started restoring the Time Machine backup

The format of Macintosh HD before the backup was APFS (case-insensitive). I didn’t think this change would matter and I would like a case-sensitive file system if possible.

My computer was restoring for about 15 minutes and managed to copy about 30GB when it suddenly failed.

Backup error

Here’s all the info about the hard drives.


As a side note, there seems to be a bunch of tiny untitled disks being listed. It goes down to /dev/disk21 which has one untitled partition that is 2.1MB in size. I don’t think I created these and I didn’t see them under Disk Utility.

Could my backup be currupted? Could my hard drive not be partitioned correctly?

Remind be never to try and install Ubuntu! Linux and macOS are incredibly similar. It’s just not worth the effort.


I found a Install macOS High Sierra.app in the root directory so I’m running that. I hope this lets me restore the Time Machine backup.

  • Any luck? I have the same with High Sierra. Basically I'm f*cked now. Really great work from Apple.
    – sebrock
    Commented Feb 27, 2018 at 10:22
  • I ran the installer I found. I manually restored individual folders from the backup using the Time Machine app. I wasn’t able to restore everything at the same time. My computer seems to be back to the way it was. I found that some of my files were already there after installing High Sierra. So erasing the disk doesn’t really erase everything. If you don’t have a backup. You might be able to recover everything somehow. Maybe Commented Feb 27, 2018 at 10:26
  • Have you found the installer sebrock? Commented Feb 27, 2018 at 10:28
  • I had to resort to reinstalling from Restore mode and then use the Migration Assistant to transfer Apps and User directory from Time Machine. As you did it seems. Pretty shitty by Apple to give this false sense of security and comfort with Time Machine that does not work as advertised.
    – sebrock
    Commented Feb 27, 2018 at 14:25

1 Answer 1


I’ve had the same problem, error while trying to restore from Time Machine Backup. I’ve solved the problem by installing a fresh Mojave, and during the installation process i choose to use migration assistant from my Time Machine Backups in my external hard drive, and it worked. It took around 4 hours to restore 850 gb.

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