To ensure compatibility with a particular computer, you should test with each version of Mac OS X that is available for that computer. The process of switching between various Mac OS System Folders on one volume is called Blessing and Deblessing System Folders, or simply changing your startup folder.

Selecting Your Startup Disk

You can make your computer start up from a CD, a network volume, or from a different disk or disk partition. To do so, you change your startup folder.

1. Open System Preferences and click Startup Disk. You see the display as in the following screen capture:



Figure 1:The Startup Disk Window

2. If necessary, click the lock icon and type the name and password for an administrator user.
3. Click the icon of the system folder or system volume that you want to use, then click Restart.

Another way to select a startup disk is to hold down the Option key as you restart your computer. You'll see the available startup disks and can select one.

If your computer is on a network and a network startup volume is available, you can start up from the network startup volume by holding down the N key as you restart your computer.

IMPORTANT: When selecting a network startup volume, be sure you select a valid network startup volume and not a network install image. Choosing a network install image reinstalls your system software and may erase the contents of your hard disk. A standard network volume icon appears as a globe and Mac OS X system folder. When you select a network volume icon, a message appears in the Startup pane describing the volume. A network install icon appears as a globe with downward pointing green arrow.