You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Restore data and repair an un-bootable Macintosh HD startup disk

my computer does not boot up. It fails with error: macOS could not be installed on your computer; undefined error 0. I tried all the below options that I found on internet, but none worked for one reason or another:


  1. restart installation from the top menu option using a macOS version (10.13.6) found on Macintosh HD. Upon restarted, it fails with the same error message as before.
  2. restart but press command-R option to enter recovery mode. With this, I tried to reinstall MacOS but it does not show Macintosh HD as installation disk. The only disk that shows up is the recovery disk, which shows up as encrypted.


So my question is: how do I repair my Macintosh HD startup disk without loosing my existing data. For now, I am currently installing Mac OS on an external hard drive and hoping that once I am able to boot from external HD, I should be able to access my existing data and back it up on the external drive.


i would appreciate any help on my question. Thanks.



MacBook Pro 13", 10.13

Posted on Dec 15, 2019 1:13 PM

Reply
Question marked as Top-ranking reply

Posted on Dec 15, 2019 7:29 PM

rahult@apple wrote:

2. restart but press command-R option to enter recovery mode. With this, I tried to reinstall MacOS but it does not show Macintosh HD as installation disk. The only disk that shows up is the recovery disk, which shows up as encrypted.

Sounds like you ran the installer from within macOS. From Recovery Mode launch Disk Utility. You may first need to unlock the drive/volume using Disk Utility before the macOS installer will recognize the volume as a valid destination. You should also try running Disk Utility First Aid on the drive to check for problems.


So my question is: how do I repair my Macintosh HD startup disk without loosing my existing data. For now, I am currently installing Mac OS on an external hard drive and hoping that once I am able to boot from external HD, I should be able to access my existing data and back it up on the external drive.

i would appreciate any help on my question. Thanks.


This sounds like the best plan. Once you have backed up your data, then I would suggest erasing the physical drive as GUID partition and APFS (top option) before reinstalling macOS. Within Disk Utility click on "View" and select "Show all devices". Your internal physical drive should now appear in the left pane of Disk Utility. Make sure to select the physical drive to erase and not just the "Macintosh HD" volume.


You may want to create a bootable macOS USB installer using these instructions:

https://support.apple.com/en-us/HT201372


If you have trouble creating a bootable High Sierra USB installer, then let us know as I have an alternative method if these instructions do not work and Recovery Mode (Command + R) do not work.


What is the exact model of your computer? You can get this information by clicking on the Apple menu and selecting "About this Mac" or by entering your serial number here.


Please startup backing up your system regularly. You never know what may happen.

Similar questions

1 reply
Question marked as Top-ranking reply

Dec 15, 2019 7:29 PM in response to rahult@apple

rahult@apple wrote:

2. restart but press command-R option to enter recovery mode. With this, I tried to reinstall MacOS but it does not show Macintosh HD as installation disk. The only disk that shows up is the recovery disk, which shows up as encrypted.

Sounds like you ran the installer from within macOS. From Recovery Mode launch Disk Utility. You may first need to unlock the drive/volume using Disk Utility before the macOS installer will recognize the volume as a valid destination. You should also try running Disk Utility First Aid on the drive to check for problems.


So my question is: how do I repair my Macintosh HD startup disk without loosing my existing data. For now, I am currently installing Mac OS on an external hard drive and hoping that once I am able to boot from external HD, I should be able to access my existing data and back it up on the external drive.

i would appreciate any help on my question. Thanks.


This sounds like the best plan. Once you have backed up your data, then I would suggest erasing the physical drive as GUID partition and APFS (top option) before reinstalling macOS. Within Disk Utility click on "View" and select "Show all devices". Your internal physical drive should now appear in the left pane of Disk Utility. Make sure to select the physical drive to erase and not just the "Macintosh HD" volume.


You may want to create a bootable macOS USB installer using these instructions:

https://support.apple.com/en-us/HT201372


If you have trouble creating a bootable High Sierra USB installer, then let us know as I have an alternative method if these instructions do not work and Recovery Mode (Command + R) do not work.


What is the exact model of your computer? You can get this information by clicking on the Apple menu and selecting "About this Mac" or by entering your serial number here.


Please startup backing up your system regularly. You never know what may happen.

Restore data and repair an un-bootable Macintosh HD startup disk

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.