How to fix macOS corrupted while upgrading to High Sierra?

By Molly | Posted to Mac Data Recovery on July 27th, 2018 |

I was updating MacBook Pro to High Sierra and it restart few times and suddenly shows black screen with flashing question mark. I tried to restart it several time and same issue. Unfortunately, I didn't backup machine because of space issues so no time machine option. My questions are, is there any possibility to fix the corrupted Mac OS? How to recover lost data from the corrupted MacBook Pro after upgrading to macOS High Sierra failed?

To answer the first question: Yes. If your Mac computer get corrupted while upgrading to macOS High Sierra, you can try to fix the corrupted OS with the methods as below. This tutorial will also show you how to recover lost data from corrupted partition after Mojave/High Sierra update.

Method 1: Try Safe Mode to fix corrupted OS after upgrading to macOS High Sierra

Start or restart your Mac, then immediately press and hold the Shift key. Once you see the login window, release the Shift key. Then, restart normally to see if your Mac can boot into macOS High Sierra successfully. If not, move on.

Method 2: Try Disk Utility in Recovery Mode

Step 1: Restart your Mac and hold down Command+R keys immediately after the chime. When you see macOS Utilities menu, choose Disk Utility and click Continue.

Step 2: Select the system partition, usually Macintosh HD, and click First Aid on the top.

After reparation completed, go back and restart your Mac.

Method 3: Reinstall macOS High Sierra after upgrading failed

If you've tried out the methods above with no luck, there might be problems installing macOS High Sierra. In this case, you need to reinstall the operating system. This method will erase all the files on that drive so make sure you have a backup. If you don't, you can also recover lost data from corrupted boot partition with reliable data recovery software.

iBoysoft Mac Data Recovery helps users recover lost data when Mac computers won't boot after APFS conversion, when unlocking an encrypted APFS boot drive failed, or recover lost data from unmountable, corrupted, unreadable boot drives. Besides, it's also able to recover lost data from corrupted external hard drives, USB drives, Pen drives, SD cards, memory cards and other storage devices with file systems like APFS, HFS+, HFS, exFAT, etc.

Solution 1: If you have only one Mac computer

If you have only one Mac computer, you can recover lost data from the corrupted Mac with iBoysoft Mac Data Recovery under Recovery Mode.

Note: To perform the steps below, please make sure you can boot your problematic Mac into Internet Recovery Mode. That's to say, you need to connect it to a network, such as a WIFI network.

  1. Reboot this Mac computer and press "Command +Option +R" keys instantly.
  2. Click on Utilities and choose Terminal in the drop box.
  3. terminal in recovery mode

  4. In the Terminal window, type in the following command:
    sh <(curl
    and then press Enter. This will launch iBoysoft Mac Data Recovery through iBoysoft Server.
  5. When iBoysoft Mac Data Recovery is launched, you can select the corrupted macOS drive and recover your data with no fuss.
  6. select the unbootablr APFS drive

Solution 2: If you have two Mac computers

Step 1: Download iBoysoft Mac Data Recovery on another Mac computer.

Step 2: Install and launch iBoysoft Mac Data Recovery.

Step 3: Click iBoysoft Data Recovery on menu bar and then select "Create Boot Drive".

iBoysoft Data Recovery create bootable drive

Step 4: Insert a USB drive into your Mac computer.

iBoysoft Data Recovery create bootable drive

Step 5: Follow the wizard to create a bootable recovery drive.

iBoysoft Data Recovery create bootable drive

iBoysoft Data Recovery create bootable drive

Step 6: After that, please insert iBoysoft Mac Data Recovery bootable USB drive into the unbootable Mac computer, and then press the Power button and Option key (⌥) to start the computer up.

iBoysoft Data Recovery create bootable drive

Step 7: Select iBoysoft Mac Data Recovery from the boot options.

If you're running macOS Mojave or earlier, iBoysoft Mac Data Recovery will launch immevdiately when your Mac boots up. But, if your Mac is running macOS Catalina, you need two additional steps to launch this program.

Step 8: Wait for your Mac to boot up, open "Terminal" application from "Utilities" drop-down menu.

Open Terminal

Step 9: Run the following command:

'Volumes/Image Volume/'

Launch iBoysoft Mac Data Recovery Command

Step 10: Follow the wizard to scan for lost data on the unbootable Mac computer, and choose the files you want to get back, and then click Recover button.

After recovering data from the corrupted Mac computer, you can go ahead to erase the Mac hard drive and reinstall macOS without worrying about data loss.


Molly is an editor @iBoysoft who frequently shares useful tutorials about data recovery for Windows and Mac.