Section 147. Archive and Install a New Mac OS X Version

147. Archive and Install a New Mac OS X Version

BEFORE YOU BEGIN

1 Install an Application from Disc or Download

143 Back Up Your Information

The next version of Mac OS X that you install on your computer, in its default behavior, will install on top of your existing installation (as an "upgrade"). If all goes well, you will put in the disc, go through the guided installation procedure, and then continue using your Mac with the same configuration settings you had been using previously. A standard Mac OS X installation adds new features to your existing system, but doesn't give you any further insight into the upgrade procedure.

147. Archive and Install a New Mac OS X Version

When troubleshooting an installation of Mac OS X, sometimes it's helpful to be able to examine the files in the previously installed version of the operating system, compare files from one version to another, and revert to earlier versions of the files if necessary. To do this, the Mac OS X Installer program provides a helpful option called Archive and Install .

NOTE

Another installation option is Erase and Install , which erases all the contents of your startup disk before installing the new version of Mac OS X on it. This option is helpful for systems that have been repeatedly reinstalled and reconfigured to the point where the new version of the operating system cannot be installed cleanly on top of it. It's also the preferred method of cleaning up a used Mac to be given to a new owner. After an Erase and Install procedure, be sure to install the additional software from the Software Restore disc that came with the Macthis includes software such as iLife and Classic.

When you use the Archive and Install option, your old version of the operating system is cleaned from the hard diskessential in many cases where the old version is full of conflicting files from multiple earlier installationsbut it's preserved in a folder on your disk called Previous Systems . The new version of Mac OS X is installed cleanly and without conflicts with earlier versions, and it even preserves your user environment, but you can access the old system files (for troubleshooting purposes or to recover important data) by browsing the Previous Systems folder.

1.	Insert the First Mac OS X Installation Disc To begin installing the new version of Mac OS X, insert the CD-ROM or DVD labeled Mac OS X Install Disc 1 (or something similar).
2.	Start the Installation Procedure In the CD-ROM Finder window that opens, double-click the Install Mac OS X icon. The Installer program opens and prompts you to enter your user password (as a security precaution, to make sure that you aren't an intruder who sat down while a legitimate user was logged in). Then you are asked to click the Restart button to begin installing Mac OS X.
3.	Open the Installation Options The Mac restarts. After it boots into the Installer program on the CD or DVD, you start to go through the introductory screens that tell you what the Installer will do. When you reach the screen where you choose the disk onto which you want to install Mac OS X, select the appropriate disk ( generally the Mac's primary hard disk) and then click the Options button at the bottom of the screen.
4.	Select the Archive and Install Option Click the Archive and Install radio button to select the installation mode that will create a clean Mac OS X installation but preserve your original system for your later perusal. TIP If you want to keep your user environment intact (as well as all the files inside your Home folder, such as your iTunes music, your digital photos, and your important documents), make sure that the Preserve Users and Network Settings check box is selected. If you don't select this option, you will have to go through the Setup Assistant screens to set up your primary user account from scratch again, and none of your original files or settings will be available after the installation process completes. Click OK to accept the options.
5.	Install Mac OS X Click Continue . Mac OS X installs itself on your system. The computer restarts after the completion of the installation process, and boots into your primary user account (or the login window, depending on your Automatic Login settings).
6.	Browse the Previous System To access the files that make up your previous system, navigate in the Finder to the Previous Systems folder (at the top level of the disk). Inside this folder are subfolders for each previously installed system, differentiated with numbers ( Previous System 1, Previous System 2 , and so on). Select the one you want and browse its contents for the items you want.