Last Week on My Mac: Are you ready for 13.3 or 9.1?

In the next day or three, Apple is expected to release the update to bring macOS Ventura to version 13.3. To help you prepare for this, I thought it might be useful to revisit how we updated just over twenty years ago, to Mac OS 9.1, as we did in 2001. When you’ve updated Ventura, you’ll then have a useful comparison.

Not only did Mac OS come on CD-ROM, but it was quite usual to install only selected parts of it. Among the new features of 9.1 was support for the burning of CDs in the Finder, and Finder support for switching between open windows. However, we had to wait for 9.2 in June 2001 before enjoying significant improvements in performance, and Mac OS X 10.0 Cheetah wasn’t released until March 2001. This is how we installed System 9.1 when it shipped in January 2001.

What it does

You wish to install Mac OS 9.1 (or upgrade to it), and have more than one hard disk volume available.

What you need

Your Mac running at least Mac OS 8.1, the Mac OS 9.1 installation CD-ROM, one hard disk partitioned into 2 or more volumes, or 2 or more hard disks.

Potential problems

Most problems arise when trying to install or update Mac OS on your only volume, hence it is better to have more than one volume available. Make sure that you do not need to upgrade your Mac’s ROM (check Apple’s support site), and if you do, perform that first. Installations can fail for many other reasons: if you have an older Mac OS on another volume, it will give you a fall-back whilst you sort the problem out. You may also find extensions and applications that are incompatible with the new Mac OS. Be prepared to chase updates as needed.

Further info

Full instructions are given in an Acrobat installation guide on the Mac OS 9.1 CD-ROM, with late-breaking news in the Before You Install file. Also check tech notes in the Apple TIL, at (now Apple’s Support Knowledgebase here)


  • Back everything up.
  • Read the installation guide and release notes.
  • Using the new Disk First Aid, check and repair disks.
  • Update hard disk drivers.
  • Run the installer, exploring options.
  • Restart from new Mac OS and configure.

Setting It Up


You should only install a new version of Mac OS on a fully healthy and backed-up Mac. Once you’ve made a complete backup, insert the installer CD and read carefully through the installation manual, the Before You Install file, and any other readme files. Then, open the Disk Tools folder on the CD and run the new version of Disk First Aid.


Once you have checked (and repaired) all mounted volumes, open the Drive Setup provided on the installer CD-ROM. Although the Mac OS installer will by default update any disk drivers it can, you will find it best if you do this manually first, and then restart your Mac, so the updated drivers ‘take’.


Once restarted (you don’t have to start up from the CD), run the installer, which is largely self-explanatory. If you’re updating a volume that already has Mac OS on it, perform a clean install by selecting this as one of the install options. You may wish to use the freeware Clean Install Assistant to help move old System Folder contents over easily.


Although recent installers have improved considerably, you should normally opt for a ‘custom’ installation, rather than just accepting that recommended. This enables you to browse through the components to be installed, and to ensure that nothing important to you is missed out. Try to get these right now, rather than having to return later to add bits you forgot.


Don’t be afraid to check what is in the Recommended Installation for each component, either. There are a very large number of items contained in the Mac OS 9.1 install item, some of which you won’t want, and some of which you’ll miss. Take your time and browse these thoroughly, or you may find yourself running the installer again to locate missing components.


Once complete, use the Startup Disk control panel to select the volume containing Mac OS 9.1, and restart. You may find you’re missing drivers for essential devices, such as your Graphire pad. It is wisest to start off with ‘generic’ mice and a minimum of peripherals. Work your way through the Mac OS Setup Assistant, configure Memory to your taste, and away you go.

Reformatted from the original, first published in MacUser volume 17 issue 10, 2001.