I’m writing this post to be more like a personal reminder in case I find myself in a similar situation in the future. I don’t know if this is the simplest or quickest method to install the components needed to use the Classic environment on a Mac that can’t boot from Mac OS 9 directly, but this is what worked for me, and it seems simple enough. If it helps other people, all the better.
The problem
I wanted to use a few Classic applications on my iBook G4/800 running Mac OS X 10.4.11, and I was prepared to install Mac OS 9.2 via an original CD-ROM I own. However, I had forgotten that this iBook, a late 2003 model, can’t boot into Mac OS 9. I was not at home, otherwise I would have probably tried to install Mac OS 9 from another vintage Mac capable of booting into Mac OS 9, while putting the iBook in Target Disk Mode. Or perhaps I would have just copied the Mac OS 9 System Folder from my Titanium PowerBook G4/400.
Simply copying the System Folder from my Mac OS 9 Installation CD didn’t work, in case you were wondering.
The procedure
But having only the iBook and an Internet connection, this is what I came up with:
1) Download NetBoot for Mac OS 9 from this page on the Apple KnowledgeBase. It’ll be a DMG file called NetBoot9.dmg.
2) Mount the DMG file, and you’ll see four language folders. Choose your preferred one, then double-click on the NetBoot.pkg package and follow the Installer prompts. The NetBoot Installer gives an error at the end of the installation. This doesn’t seem to matter for what we’re trying to achieve.
3) Now, in the root directory of your Mac’s drive, you should see a folder called NetBootInstallation. If you try to open it, the Mac will warn that you don’t have sufficient access privileges. Open the Info panel for the folder (⌘-I), expand the Details in the “Ownership & Permissions” section, change the owner by clicking on the small padlock icon and authenticating with your admin credentials, and finally give yourself Read & Write permissions for the folder.
Ignore the ‘Zero KB’ size. The folder is not empty.
4) You’ll find three files inside NetBootInstallation. Double-click on NetBoot HD.img and mount the image.
5) Copy the contents of the image — Applications (Mac OS 9) and System Folder — to the root directory of the Mac’s drive.
6) Now open System Preferences → Classic.
7) In the Classic preference pane, under “Select a system folder for Classic”, you should see the System Folder you copied on Step 5 appear below the Mac’s drive name. Select it, and start Classic.
8) You should get two warnings when you first start Classic. The first is about the version of QuickTime being old, and you can dismiss it for now. The second is about Classic having to update files in “System Folder” (see image above). Click Update. At this point, Classic will proceed with its startup process and complete successfully. The Mac OS version will be 9.2.2.
An alternative method is to use Pacifist (older versions for PowerPC Macs are on this page). You mount the NetBoot9.dmg image. Then, after installing Pacifist, you select Open Package from the main window, navigate until you find the NetBoot.pkg package mentioned above on Step 2. Open the package, select NetBoot HD.img, then click the Install button on Pacifist’s toolbar. Tick the “Use Administrator Privileges” checkbox, authenticate when prompted. Then it’s the same procedure we saw above from Step 3 onward. (The only difference is that when you open the NetBootInstallation folder, you’ll only find the NetBoot HD.img image).
System Folder 
Very interesting – and helpful for people who keep old Macs either for fun or to be able to run old software when required Or both. I seem to recall having enormous difficulty installing OS9 on a G4 that was capable of booting from it. What I hadn’t realised (and I could be wrong here – it’s several years ago) is that the HD was formatted HFS+ and I think it had to be reformatted as Mac OS Standard (or similar name) with the instruction that it was to be botable. After that, the OS9 installation went ahead fine from an install-CD.
nice little work around! 👍🏻
If anyone is like me, I’ve got various OS9 folders and images backed up in various locations, and I often lose track of which one is the “perfect” version…plus what with all the model specific versions…is always nice to have a write up out there!
You can also use the “Mac OS 9 Install Disc” that came with late PPC Macs, such as the Mac mini, to install the necessary bits for Classic because it contains a full OS 9 System and Applications folder in several languages.
@Adrian King – OS 9 has no issues booting from a HFS+ volume; all it needs are the “OS 9 Drivers”; when partitioning a drive using Disk Utility, this checkbox needs to be ticked for a volume to be OS 9-bootable.
Impressive hack, I’ve never seen someone use the NetBoot Mac OS 9 install as a Classic folder.
Technically that does work, but my guess is you’re missing some classic Mac apps in the process.
The “official” way is to use the Classic Only Install from a Mac restore disk, which uses a .pkg file that injects a pre-patched System Folder and all the Mac OS 9 apps to the system. It’s available on the Aluminum PowerBook (and this iBook’s) restore discs… which you can probably find online too.
Thank You so much ! This saved my life !!!! Kudos
From the bottom of my heart, I want to say thank you, thank you, thank you!! My goodness, your article has helped me tremendously. As a novice to older Macs, I had such a hard time getting to know my machine (iBook G3 Clamshell). It came with 10.3.9 but all I ever wanted to do was run classic applications on it. Thanks to your very helpful steps, I was able to do just that! I just had to screenshot this article in case I ever need it in the future. I have no doubt this won’t help hundreds more old mac users. Thanks again!