Perform an Upgrade Install of Lion on Your Mac

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Perform an Upgrade Install of Lion on Your Mac

Upgrade Install of Lion screenshot


Apple changed the installation process for Lion slightly from earlier versions of OS X. While the process is fundamentally the same, there are differences caused by the new distribution method for Lion, which is sold only through the Mac App Store.

Instead of having physical media (a DVD) to install from, you use the Lion installer app you download from the Mac App Store.

In this step-by-step guide, we're going to look at installing Lion as an upgrade to Snow Leopard, which should be the current working installation of OS X on your Mac.

What You Need to Install Lion

  • A copy of the Lion installer. This is available from the Mac App Store. Once you purchase Lion, the installer application is downloaded to your Mac and will appear in the Dock. The installer is actually located in your Applications folder, and is around 4 GB in size. You must have Snow Leopard 10.6.8 installed to purchase and download the Lion installer, however, once the download is complete, you can copy the installer application to any Mac that meets Lion's minimum operating requirements.
  • A disk or partition to install the Lion OS on. The Lion installer fully supports internal drives, both conventional and SSD (Solid State Drive) models. The Lion installer also supports external drives, but they must connect to your Mac by USB 2.x, FireWire 400 or 800, or Thunderbolt. eSATA drives aren't likely to work as boot drives; not because Lion won't work with them, but because most add-on eSATA interfaces don't support booting under OS X.
  • A minimum of 8 GB of free space to install Lion. You can get by with 8 MB, but practical concerns, such as having enough space to install third-party applications and get a bit of work done, mean that 60 GB of free space is a better minimum threshold.
  • A minimum of 650 MB of free space to install the Lion Recovery Partition. When you install Lion, it creates two partitions. The main partition houses the Lion OS and anything else you care to add. The second partition is a small 650 MB partition that contains recovery tools. You can use the Recovery Partition if you ever need to use troubleshooting utilities, such as Disk Utility, on the main boot volume; you can also use the partition to re-install Lion, should the need arise.

With everything ready, let's start the installation process.

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Install Lion - The Upgrade Process

Lion Installer defaults to the current startup drive screenshot


Before you begin the Lion upgrade process, it's a good idea to back up your existing OS X installation. You can do this using numerous backup utilities, including Time Machine, Carbon Copy Cloner, and SuperDuper. The utility you use to perform the backup isn't that important; what's important is having a current backup of your system and user data before you start the upgrade to Lion.

Our choice is to have a current Time Machine backup and a clone of the current boot volume.

With the backup out of the way, let's continue with the Lion upgrade installation process.

Installing Lion

This is an upgrade install of Lion, which means you'll replace your current installation of Snow Leopard with OS X Lion. The upgrade should not affect your user data, account information, network settings, or other personal settings. But because everyone has different applications and uses for their Mac, it's not possible to determine that everyone will have zero problems with any OS upgrade. That's why you did a backup first, right?

Starting the Lion Installer

When you purchased Lion, the Lion installer was downloaded from the Mac App Store and stored in the /Applications folder; the file is called Mac OS X Lion. It was also installed in the Dock for easy access.

  1. Before you start the Lion installer application, close any other applications you may be running.
  2. To start the Lion installer, click the Lion installer icon in the Dock, or double-click the Lion installer located at /Applications.
  3. When the Lion installer window opens, click Continue.
  4. The terms of use will appear; read them (or not) and click Agree.
  5. The Lion installer defaults to installing on the current startup disk; this should be the correct drive for most users. If you want to install Lion to a different drive, click Show All Disks, then select the target disk. Click Install to continue.
  6. You'll be asked for your administrator password; enter the password, and then click OK.
  7. The Lion installer will copy its basic startup image to the selected drive, and then restart your Mac.
  8. After your Mac restarts, the Lion installer will take about 20 minutes (your mileage may vary) to install OS X Lion. The installer will display a progress bar to keep you informed of the installation process.

If you have more than one monitor attached to your Mac, be sure that all monitors are turned on. For some reason, when we installed Lion, the progress window was displayed on my secondary monitor, which was off. Although there are no ill effects from having your secondary monitor turned off, it can be downright confusing not to see the progress window.

Once the installation is complete, your Mac will restart.

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Install Lion - Completing the Lion Upgrade Installation

Completing the Lion Upgrade Installation screenshot
After the Lion installer restarts, your only a few minutes away from your new OS.


The first startup can take a bit of time, as Lion fills its internal cache files with new data, so it may take a while before your desktop displays. This delay is a one-time event; subsequent restarts will take the normal amount of time.

The Lion installer window will display, with a "Thank You" note for installing Lion. You may also see a More Info button at the bottom of the window; if you do, click the button to see a list of applications the Lion installer found that are incompatible with Lion. Incompatible applications are moved to a special folder called Incompatible Software, located in the root directory of your startup drive. If you see any applications or device drivers in this folder, you should contact the developer to obtain Lion updates.

To dismiss the Lion installer window, click the Start Using Lion button.

Updating Software for Lion

Before you start exploring, there is one more task to perform. You need to check for software updates for system and device drivers, as well as for applications.

Use the Software Update service, located under the Apple menu, to check for updates. You may find new printer drivers, as well as other updates, ready for your Mac. Also check the Mac App Store, to see if any of your applications have Lion updates available.

That's it; your Lion update is complete. Have fun exploring your new OS.