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.
My personal choice is to have a current Time Machine backup and a clone of the current boot volume. You can find instructions for the backup method I use in the following article:
With the backup out of the way, let's continue with the Lion upgrade installation process.
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.
- Before you start the Lion installer application, close any other applications you may be running.
- To start the Lion installer, click the Lion installer icon in the Dock, or double-click the Lion installer located at /Applications.
- When the Lion installer window opens, click Continue.
- 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.
- You'll be asked for your administrator password; enter the password, and then click OK.
- The Lion installer will copy its basic startup image to the selected drive, and then restart your Mac.
- 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.
A note for multiple monitor users: If you have more than one monitor attached to your Mac, be sure that all monitors are turned on. For some reason, when I 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.