Downloading it now. I love logging in to my iMac from work and doing it. Before the iPad, I had to wait until I got home!

Very cool! Thanks...

DLed Lion, tried to install but got a error message (something like...) "Lion" could not be installed. A 'recovery disk' con not be created. What gives?

I'm gonna wait a month or 2 & let you guys iron out all the bugs before I give Lion a try.

I like the idea of burning it on a dvd though. I believe that is the way I'll go.

What are you installing it on?

Specs...we need specs.

Tried to install it on an iMac 3.06 GHz, Intel Core 2 Duo, OS X version 10.6.8, 4 GB RAM.
785 GB Free space. However, I also have a WinXP partition. I wonder if the XP partition is the culprit? Apple recommends.... (Bummer! I paid for it and the App store shows it's installed but it's NOT!)

"What to do if the installer warns that no Recovery HD can be created

Some disk partition configurations may result in the OS X Lion installer reporting that it could not create a Recovery HD. In these situations, even if you are permitted to continue the install, you should quit the install and create an external, bootable OS X Lion hard drive with a Recovery HD, first. You will be able to return to the upgrade to OS X Lion on your computer's boot drive after creating the external Recovery HD.

Important notes

Your storage device must have at least 13 GB available (after formatting) to install Lion and an Internet Restore partition.
These steps will erase and reformat the storage device. This article will instruct you on setting up the storage device to use the GUID partition scheme and the Mac OS Extended (Journaled) format, which are required to install Lion and an Internet Restore partition on your external storage device. You should back up any important files that are on the device to a different drive.
This procedure will install a version of the OS X Lion that is compatible with the Mac it was created with. Using this Lion system with a different kind of Mac may produce unpredictable results.
Your computer's serial number will be sent to Apple to help authenticate your request to download and install OS X Lion."

From the article I linked...


But wait a second—how exactly is this going to work? Surely an entirely new operating system can't be installed on top of the currently running operating system by an application stored on the same volume. Without a plastic disc to boot from, how is it even possible to upgrade a standalone Mac with just one hard drive?

These questions probably won't occur to an average consumer, which is sort of the point, I guess. Sure enough, if you just close your eyes, launch the installer application, and click your way through the handful of screens it presents, your Mac will reboot into what looks like the standard Mac OS X installer application from years past. When it's done, your Mac will reboot into Lion. Magic!

Okay, it's not magic. The answer is actually technically obvious, but also quite unprecedented in the Mac's history. Once you've selected the target disk, the Lion installer application will repartition the disk, carving out a 650MB slice of the disk for its own use.

Don't worry, all existing data on the disk will be preserved. (Mac OS X has had the ability to add partitions to existing disks without destroying any data for many years now.) All that's required is enough free space to reshuffle the data as needed to make room for the new partition.

Here's an example from my testing. I started with a single 250GB hard drive split into two equal partitions: the first named "Lion Ex," currently running Snow Leopard, and the intended target of the Lion install, and the second named "Timex," the Time Machine backup volume for Lion Ex. The output from the diskutil list command appears below.

/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *250.1 GB disk1
1: EFI 209.7 MB disk1s1
2: Apple_HFS Lion Ex 125.0 GB disk1s2
3: Apple_HFS Timex 124.6 GB disk1s3
Now here's that same disk after installing Lion, with the new partition highlighted:

/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *250.1 GB disk1
1: EFI 209.7 MB disk1s1
2: Apple_HFS Lion Ex 124.5 GB disk1s2
3: Apple_Boot Recovery HD 654.6 MB disk1s3
4: Apple_HFS Timex 124.6 GB disk1s4
The new partition is actually considered a different type: Apple_Boot. The Recovery HD volume won't be automatically mounted upon boot and therefore won't appear in the Finder. It's not even visible in the Disk Utility application, appearing only as a tiny blank space in the partition map for the disk. But as shown above, the command-line diskutil program can see it. Diskutil can mount it too.

Doing so reveals the partition as a normal HFS+ volume. The top level contains a directory named com.apple.recovery.boot which in turn contains a few small files related to booting along with an invisible 430MB internally compressed disk image file named BaseSystem.dmg. Mount that disk image and you find a 1.52GB bootable Mac OS X volume containing Safari, most of the contents of the standard /Applications/Utilities folder (Disk Utility, Startup Disk, Terminal, etc.), plus a Mac OS X Lion installer application. In other words, it looks a lot like a standard Mac OS X installer DVD.

This is the partition that the Mac will boot from when you install Lion. The files to install will be read from the Lion installer application downloaded earlier from the Mac App Store. After the installation is complete, the Recovery HD partition remains on the disk. Hold down ⌘R during system startup to automatically boot into the Recovery HD partition. (Holding down the option key during startup—not a new feature in Lion—will also show the Recovery HD partition as one of the boot volume choices.)

Booting from the recovery partition really means mounting and then booting from the BaseSystem.dmg disk image on the recovery partition. Doing so presents a list of the traditional Mac OS X install disc options, including restoring from a Time Machine backup, reinstalling Mac OS X, running Disk Utility, resetting your password, and so on. There's also an option to get help online, which will launch Safari. Including Safari on the recovery partition is a nice touch, since most people's first stop when diagnosing a problem is Google, not the Genius Bar.

The upshot is that after all the file compression magic added in Snow Leopard to reduce the footprint of the OS, Lion steals over half a gigabyte of your disk space as part of its installation process, and never gives it back. The partition's name makes Apple's intent clear: it's meant as a last-ditch mechanism to diagnose and repair a Mac with a hosed boot volume. (Hosed, that is, in the software sense; existing as it does on the boot disk itself, the recovery partition won't be much use if the disk has hardware problems.)

Apparently Apple has decided that the ability to boot a Mac into a known-good (software) state is well worth sacrificing a small amount of disk space. MacBook Air owners or other Mac users with diminutive solid-state disk drives may disagree, however. In that case, the disk space can be reclaimed by some judicious repartitioning with Disk Utility (or the diskutil command-line tool) while booted from another disk. But don't be surprised when the fellow at the Genius Bar frowns a little at your deviation from the Apple Way.

Well that's new, and kind of a step towards Windows installations. Pre-Lion any HD could boot any Mac as long as the version was in specs for the machine. For example I have external drives for maintenance. The 10.5.8 one can boot anything from a G4 to an Intel model. The 10.6.8 one can only boot Intels but it can boot any Intel. I'll have to check out more before passing judgement but it seems that they're making them harder to service.

Regarding OS the version being in specs for the hardware, Windows has a huge leg up on that. I have what's called Hiren's boot diagnostic CDs for Windows machines. It runs a version of mini-XP that can boot just about any machine. It can boot brand new Core i7s or 13 year old Celerons.

Again, the App Store indicates that 'Lion' was 'installed' when quite clearly it was NOT.
And -of course- it won't let me 'install' it again.
I do NOT want to pay for it again. How can I possibly try again and install it?
This is NOT what I expected from 'Lion'....grrrrr!

Mike, I would try opening the App Store, click the Store menu, scroll down and select Check For Unfinished Downloads.