Mac OS X,  Mass Deployment

Making and Using an Installer Disk for Lion

When I got my MacBook Air, I thought that little USB disk was the coolest. I took it immediately to another computer, popped it in and booted. As many of you probably know, it didn’t work. I think the idea of diskless restores will take me a little while to get used to. I also think I like to have a DVD for every OS I use. Many of my customers also have policies that they have to.

Now I know you can boot holding down Command-R and go into recovery mode (boot to that awesome, hidden restore partition). And I know that you’re basically running a bless command on Apple’s cloud instance of a NetInstall instance. And I do think that should likely be the first step for most users when they need to reinstall their operating system. But picture your firewall when you go to reinstall 30 machines that way. I’m guessing you don’t like the smell of burnt plastic any more than I do.  So let’s look at creating an installer DVD.

When you download Lion, it makes a bundle in /Applications called Install Mac OS X Lion. There’s a cute progress bar as that folder gets populated and when it’s done, you can double-click on it to start your Lion install. Or, you can control-click on it, compress it and then let it install. Control-click (or right-click) on it and choose Show Package Contents to see Contents. Go to SharedSupport and you’ll see InstallESD.dmg.

Extract InstallESD.dmg and you will see the contents of a traditional OS X Installation disk. On a MacBook Air you can make a NetInstaller of that wicked fast… Or on any old computer, open Disk Utility.

To burn the disk image, click on InstallESD.dmg in the Disk Utility sidebar and then click on the Burn icon. The contents will then burn to the DVD.

Then try and boot to the DVD. Provided you boot, you have now created a bootable installer for Lion. The boot process I think is slower than in previous OS releases (especially compared to Recovery Mode). When the boot process completes, you’ll be greeted with 4 options: Restore from Time Machine Backup, Reinstall Mac OS X (which I’m guessing will eventually say Reinstall OS X), Get Help Online (which you need functional DNS to use) and Disk Utility (to create those RAIDs, repair disks and perform other tasks we all love so much). The Utilities menu has the other options we often need, including Firmware Password Utility, Network Utility and Terminal. If you’re using Encrypted Time Machine volumes, you’ll need a password to restore. If you’re using FileVault 2 (Full Disk Encryption), you’ll need to use the Unlock button in Disk Utility and then be prompted for a password for the volume. You’ll then be able to manage the disk as you otherwise would. This should answer the question a few people have asked about how to repair permissions and disks if you use FileVault in Lion.