Start up from macOS Recovery

  • When trying to repair the disk I get the exit code 8. Invalid node structure (8, 0) Invalid B-tree node size (8, 0) I also have Bootcamp installed and Windows can see the drive; it seems normal to me there. But it is formatted as Mac OS Extended so Windows can't do anything with it. Do you have any idea what I can do other than reformat?
  • “Max OS X Can’t repair the diskyou can still open or copy files on the disk, but you can’t save vchanges to files on the disk. Back up the disk and reformat as soon as possible” So, I plugged in another hard drive, a Seagate, to back up the My Passport HD and a message pops up to say that it’s not possible to do copy the files over.
  • The Disk Utility on macOS is a useful tool for fixing any disk-related issues or performing tasks that involve the hard drive. But this tool is not impregnable. Flaws, such as the “Couldn’t Unmount Disk” error, can happen from time to time. When this happens, simply follow the solutions listed above and you’ll be good to go.

Click on the “First Aid” icon in Disk Utility’s toolbar (found in the top-right corner of the “Disk Utility” window) to start the repair process. Read the confirmation dialog to confirm you’ve selected the correct drive, then click “Run” to start the disk repair process. Read the warning message as well, then click.

Mac

Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:

Apple silicon

Turn on your Mac and continue to press and hold the power button until you see the startup options window. Click the gear icon labelled Options, then click Continue.

Intel processor

Make sure your Mac is connected to the Internet. Then turn on your Mac and immediately press and hold Command (⌘)-R until you see an Apple logo or other image.

If you're asked to select a user you know the password for, select the user, click Next and enter their administrator password.

Reinstall macOS

Select Reinstall macOS from the utilities window in macOS Recovery, then click Continue and follow the onscreen instructions.

Follow these guidelines during installation:

  • If the installer asks to unlock your disk, enter the password you use to log in to your Mac.
  • If the installer can't see your disk or notifies you that it can't install macOS on your computer or volume, you may need to erase your disk first.
  • If the installer offers you the choice between installing on Macintosh HD or Macintosh HD – Data, choose Macintosh HD.
  • Allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac may restart and show a progress bar several times, and the screen may be empty for minutes at a time.

When the installation is complete, your Mac may restart to a setup assistant. If you're selling, trading in or giving away your Mac, press Command-Q to quit the assistant without completing setup. Then click Shut Down. When the new owner starts up the Mac, they can use their own information to complete the setup process.

Other macOS installation options

When you install macOS from Recovery, you get the current version of the most recently installed macOS, with some exceptions:

  • On an Intel-based Mac: if you use Shift-Option-Command-R during startup, you'll be offered the macOS that came with your Mac, or the closest version that is still available. If you use Option-Command-R during startup, in most cases you'll be offered the latest macOS that is compatible with your Mac. Otherwise you'll be offered the macOS that came with your Mac, or the closest version that is still available.
  • If the Mac logic board was just replaced, you may only be offered the latest macOS that is compatible with your Mac. If you've just erased your entire startup disk, you may only be offered the macOS that came with your Mac, or the closest version that is still available.

You can also use these methods to install macOS, if the macOS is compatible with your Mac:

Macos Cant Repair The Disk My Passport

  • Use the App Store to download and install the latest macOS.
  • Use the App Store or a web browser to download and install an earlier macOS.
  • Use a USB flash drive or other secondary volume to create a bootable installer.