Start from the installation DVD
To start your Leopard installation, simply insert the Mac OS X Leopard Install DVD and double-click the Install Mac OS X icon.
You can also start by inserting the Install DVD and restarting your computer while holding down the C key, or by selecting the Install DVD as your startup disk using Startup Disk preferences.
Note: Mac OS X 10.5 cannot be installed on a UFS-formatted volume; see this article for more information.
Default installation if Mac OS X is already installed
When the Mac OS X Installer opens, follow the onscreen instructions to select your Mac OS X startup disk. Eligible disk volumes appear with a green arrow icon. By default, the installer will upgrade your currently-installed version of Mac OS X to Mac OS X 10.5 Leopard.
Note: If you wish to install in a different manner, click the Options button on the "Select a Destination" window; see below for more information about installation options.
If you need to quit the installer before the actual installation process begins, choose Quit Mac OS X Installer from the Mac OS X Installer application menu, and then click Startup Disk to select a startup disk for your computer.
Note: Once the installation process has started, you should wait until it ﬁnishes.
If the installer does not detect an existing version of Mac OS X on your hard disk, or if you click Options on the "Select a Destination" window, an installation sheet will appear asking you to choose between Install Mac OS X, Archive and Install, or Erase and Install. Select a method, then click OK to continue.
Install Mac OS X choice
This installs Mac OS X for the first time on a disk that does not have Mac OS X currently installed.
Archive and Install choice
This option moves existing system files to a folder named Previous System, and then installs a new copy of Mac OS X. This option is available only for volumes with Mac OS X already installed. Usually, if you select this method, you will want to also select (check) "Preserve Users and Network Settings" which imports existing user accounts, home folders, and your network settings into the new system.
Erase and Install
If you want to erase your disk before installing Mac OS X Leopard, select this option then click OK. Important: This option erases the entire disk, so make sure you've backed up your important ﬁles ﬁrst.
If you want to partition your disk before installing, use Disk Utility (choose Disk Utility from the Utilities menu). In Disk Utility, click Partition. If you
partition the disk, you can select a disk format including Mac OS Extended (Journaled), Mac OS Extended (Case-Sensitive), and Mac OS Extended (Case-Sensitive, Journaled). In most cases, you should choose Mac OS Extended (Journaled). After partitioning, quit Disk Utility to return to the Leopard Installer. Important: Partitioning the disk erases the entire disk, so make sure you back up your important ﬁles ﬁrst.
Installing on a computer with a third-party SCSI card
If you have a third-party SCSI card installed in your computer and you cannot start up Mac OS X 10.5, attach a device or terminator to one of the card’s ports. If you continue to have issues, try removing the card. Contact the manufacturer of the card for more information about using the card with Mac OS X.
Installing on a computer with a third-party video card
If you have a third-party video card installed in your computer, you may need to remove it before you install Mac OS X 10.5. Contact the manufacturer of the card for more information about using the card with Mac OS X 10.5.