For Mac OS 8.5 through 9.2 information, see technical document 58176, "Mac OS 8.5, Mac OS 9: Performing a Clean Installation".
A normal system software installation modifies and updates the existing System Folder. A clean installation disables the existing System Folder, leaving all files in place, and creates a new System Folder.
A clean system installation brings the system software back to the standard configuration. This is necessary when system software has been damaged or modified, preventing a normal installation. It is also useful in troubleshooting.
Clean Install Instructions
Follow these instructions in the order presented.
Starting from the Mac OS 8 CD
2. Restart your Macintosh.
3. As soon as you hear the startup chime, hold down the letter 'C' on the keyboard until you see the "Welcome to Macintosh" message.
4. As the computer starts up, you should see the "flying CD" background pattern- this will confirm that you are starting from the CD.
5. If the computer does not start from the CD, shut down the computer, turn on the computer and immediately hold down the Command-Option-Shift and the large Delete key simultaneously. Hold down these keys until you see the "Welcome to Macintosh" message.
6. If you a receive a system error while starting from the CD, please see the section entitled "Cannot Boot from Mac OS 8 CD When AppleTalk is Off" in article 24160: "Mac OS 8: Late Breaking Information."
7. At the desktop, the Apple Macintosh CD's icon should be in the upper-right corner of your screen with your hard drive's icon below it. If any other hard drive appear above the Apple Macintosh CD, go to the Control Panels under the Apple Menu, open the Startup Disk item, select the Apple Macintosh CD, close all open windows and restart. The Apple Macintosh CD should then appear above the hard drive.
8. If you have successfully started from the Mac OS 8 CD, double-click the "Mac OS Install" icon or the "Install Mac OS 8.1" icon, then proceed to the section entitled "Installing Mac OS 8".
Starting from the Disk Tools diskette
Note: These steps require a Mac OS 8 CD and Apple CD ROM drive.
2. Insert the appropriate Disk Tools diskette in the floppy drive, and turn on the computer. At the desktop, the Disk Tools floppy disk's icon should be in the upper-right corner of your screen with your hard drive's icon below it.
3. Disk Tools Disk 1 is designed for use with all non-PowerPC machines except the PowerBook 190.
4. Disk Tools Disk 2 is designed for use with all PowerPC computers and the PowerBook 190.
5. Insert the Mac OS 8 CD and double click the "Mac OS Install" icon or the "Install Mac OS 8.1" icon, then proceed to the section entitled "Install Mac OS 8".
Starting from the Install Me First diskette
2. Insert the Install Me First diskette in the floppy drive, and turn on the computer. The installer program will launch automatically on startup.
Installing Mac OS 8
2. When the "Select Destination" screen comes up, select the appropriate disk in the Destination Disk pop-up menu.
3. Check the box marked "Perform Clean Installation", then click the Select button.
4. Read the Important Information on the next screen and click Continue.
5. Read the licensing agreement and click Continue.
6. At this point you may customize your installation. Refer to your Mac OS 8 manual for descriptions of the optional components listed.
7. If you are using a non-Apple hard disk, click the Options... button and uncheck the Update Apple Hard Disk Drivers option. It is very
important that you check with the vendor of your non-Apple hard disk to confirm that your hard disk driver will be compatible with Mac OS 8 before you start the installation.
8. Click the start button. The installer will check your hard disk and attempt to repair any faults that it finds. If it is unable to repair them, you should back up the hard disk and reinitialize it using the appropriate formatting utility for that drive. For Apple drives, use Drive Setup.
Troubleshooting
These steps assume you are using the Clean Install of system software for troubleshooting purposes.
1) Verify Issue Resolution
2) After performing a clean installation, verify that you resolved the difficulty before adding anything to the new System Folder. Adding items to the System Folder before resolving your difficulty defeats the purpose of performing a clean installation.
3) Install Non-Standard Items
You can now reinstall the non-standard items from the old System Folder (now named "Previous System Folder") such as fonts, extensions, and control panels. If possible, you should reinstall these items from their original disks.
If the original disks are not available, you may move the nonstandard items from the Previous System Folder to the new System Folder. Be careful not to replace anything that is already in the new System Folder. Only move items that are not already in the new System Folder. Open each corresponding folder within the System Folder and the Previous System Folder and then compare the contents. Move up to 5 items that are not already in the new System Folder and its sub folders from the Previous System Folder and its sub folders.
Restart your Macintosh.
Verify that the Macintosh is still starting up properly and that basic functions are working properly.
Repeat Steps 2-4 until all non-standard items have been moved from the Previous System Folder to the new System Folder.
4) Final Steps
Verify your applications are performing normally. If not, refer to the application manual or contact the vendor. When the Macintosh behaves as expected and you are sure that all needed items from the Previous System Folder are transferred or reinstalled, move the Previous System Folder to the Trash, and choose Empty Trash from the Special menu.