I have one Mac running 10.7.5 and another running 10.6.8 that can be upgraded to 10.7.5. Unfortunately, I don't have an admin password for either, because the previous owner of the first died suddenly and the owner of the second -- that's me! -- can't remember the password. I'm trying to create a bootable external volume from an ESD dmg file but when I follow the procedures for doing it using the Disk Utility Restore option, it demands a password even though I'm not trying to modify anything on the computer.

Is there any way of getting around this using, perhaps, dd?

If I borrow access to another Mac, does it matter what OS version it's running if I want to use Restore? (I couldn't run the installer on a Mac running 10.11. It said something about operating system incompatability.)

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    Which instructions are you following, at which step does it require a password? Can‘t you just create a new admin user on either machine? – nohillside Sep 5 '19 at 8:59

You can just set a new admin password and then you're able to enter the password for cloning the ESD.dmg file (which you'll then perhaps not even need at all).

You can set a new password by doing the following:

1) Power on the Mac while holding down the Cmd key and the S key

2) When the Mac has booted into single-user mode, type the following commands:

mount -uw /
launchctl load /System/Library/LaunchDaemons/com.apple.opendirectoryd.plist
passwd roger

You need to replace "roger" with the actual account name for your admin user.

When you're done, restart the system by typing this command:


Now you should be able to login with the newly entered password.

For others: If you're running a newer version of macOS (10.8+) you can do the same in a much simpler way by holding down the Command and R keys while booting up to start in Recovery mode. From there open Terminal from the Utilities menu. Enter the command resetpassword and you'll be guided through the rest of the process.

  • This worked, on at least one of the Macs at issue: an iMac running 10.7.5. Thanks much! I'll soon be trying it on my old Macbook running 10.6.8, which I hope to be able to upgrade to 10.7.5. I will also be trying the second method on a MacBook Pro running 10.9.x, but which is, I think, capable of running 10.11. – Roger Aarons Sep 7 '19 at 12:57
  • @RogerAarons Good to hear! If it worked for you, please mark the answer as accepted! – jksoegaard Sep 7 '19 at 13:25

To be able to install/upgrade a new OS without completely erasing the drive (do you have backups?) you will need to either know the primary administrator account password for the machine, or be able to reset them.

You are going to need physical installer media to be able to reset the passwords, and restoring an InstallESD.dmg file from the bowels of a macOS installer is not going to be sufficient – sure, it can install the actual OS for you, but it is the wrapper (called BaseSystem) which holds the tools for resetting passwords.

What will work, though, is a Snow Leopard DVD, a USB-stick that has had the whole Snow Leopard DVD imaged onto it (something Disk Utility on OSX 10.5 to 10.9 can do easily for you) or a full Lion installer app that has been converted to a USB-stick installer with createinstallmedia or a GUI wrapper such as DiskMaker X or MacDaddy Install Disk Creator.

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