Emulating Mac OS 9 on macOS 10.15

9 June 2020
Mac OS 9 on macOS 10.15
Mac OS 9 on macOS 10.15

For several years now, I have had an old iMac G3 from about 2000 sitting around in one corner of my home office. It works perfectly fine, but I rarely start it up because I really don’t have much of a use for it most days. Occasionally, I play old games or run old software that I still have from 20 years ago, but those occasions are few and far between.

But today boredom and curiosity got the better of me.

I fired up the old iMac and, as usual, it reliably started right up. Compared to my modern MacBook Pro, however, it is obviously noisy, slow and the resolution is terrible. Those are always the first things that strike me whenever I decide to use the iMac, so the thought I had today was: why not try to emulate Mac OS 9 on my MacBook Pro running macOS 10.15 Catalina instead of always having to boot my iMac?

iMac Running Mac OS 9
iMac Running Mac OS 9

Emulation cannot, of course, replace the experience of actually using the iMac though since it doesn’t give you the full immersion experience of using an authentically vintage computer. Whenever I sit in frontend of that old CRT screen listening to it hum, I always feel a bit like I did back then when I was in school and using AppleWorks on one of these colorful machines to type up my homework — usually some essay first written by hand.

But I digress. I decided to try to emulate Mac OS 9 on my MacBook Pro so that I wouldn’t always have to start the iMac whenever I felt like playing Age of Empires, Civilization III, the original Tomb Raider or Railroad Tycoon II. Plus, I figured I could really jack up the specs on the emulator which would allow me to play a few more games that my iMac won’t run (it only has 64 MB of RAM). Not to mention I could then also run Photoshop 6 again. (the last version of Photoshop I purchased).

Researching Emulators

The first thing I did was to look around online for other people’s experiences with emulating Mac OS 9. The most commonly run emulators for older Macintosh systems are SheepShaver and Basilisk II, both of which I have used before to emulate System 7 just for fun. SheepShaver seemed to be what people were using to emulate Mac OS 9, however, so that is what I went with.

I followed the instructions on their website for setting it up which worked well and I was, with a bit more research on other websites, able to use my iMac in order to extract a valid ROM which is required to run an older Macintosh operating system. With the ROM I was able to get SheepShaver running, Next, I needed to install the operating system itself.

Installing the Operating System

The next piece that was missing though was a Mac OS 9 install disk. My iMac came with one, but it doesn’t work with SheepShaver because it came with Mac OS 9.1. SheepShaver only works up to Mac OS 9.0.4 because it does not emulate the MMU (Memory Management Unit) which was a requirement for Mac OS 9.1 and above.

Instead, I ended up downloading an image of an install CD from Macintosh Garden which is an excellent website to download vintage Mac software. I was able to get it to work with the Mac OS 9.0.4 Universal Install image.

Installing Software

I now have a bootable, usable Mac OS 9 instance on my modern MacBook Pro. It runs with 512 MB of RAM and has 4 GB of hard drive space. I was able to install most of my old games and software on it, although I did run into an issue with getting macOS 10.15 to mount some of the old Apple HFS-formatted CDs so that I could install them. As a work around, I had to use the Disk Copy utility on my old iMac to create .IMG files out of them which I could then transfer to my MacBook via a USB drive (ironcially FAT32-formatted) and then mount into SheepShaver. That was a bit of a hassle, but it worked.

I also browsed Macintosh Garden for a while and found a few new games and other bits of software that looked interesting that I am looking forward to trying out.

An Easier Solution

I spent most of a day doing what I described above just to stumble upon an easier solution later on that would have saved me a lot of hassle. I will share this solution with you now, but not without saying that I still enjoyed the whole process described above.

The solution is a pre-made instance of SheepShaver running Mac OS 9.0.4 that includes a number of utilities and other pieces of software. The ROM is also included and the whole bundle is packaged into a simple, runnable application for macOS 10.10 and above. That means, all you have to do is download it, unzip it, move it to your Application folder and run it. Mac OS 9 boots right up and you don’t have to do a thing otherwise.

You can find and download this brilliant solution for free on http://www.columbia.edu/~em36/macos9osx.html.


They say no article is complete without a conclusion. Well, mine is this: Mac OS 9 is still fun to use and the fact that I now have a lightning-fast version of it running in an emulator on my modern MacBook is a real treat and convenience factor when I get the itch to play old games.

So now, unless I want the full 20-year-old immersion experience, I no longer have to fire up the old iMac in order to run my old software. Instead, I can conveniently sit with my laptop on the couch and play like it’s 1999.

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About the Author

Alex Seifert
Alex is a developer, a drummer and an amateur historian. He enjoys being on the stage in front of a large crowd, but also sitting in a room alone, programming something or writing about history.

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  1. Dirk in Utah
    25 March 2024 3:44 am  link

    Thank you so much for your post about OS9. I have a very valuable file for genealogy covering 3000 names of my family that I developed over 15 years on an Apple Powerbook 150 using System 9. I ‘ve been accessing it for years on a 2013 iMac using SheepShaver. But when I was forced to upgrade to a newer computer, SheepShaver wouldn’t work and it was beyond me to reinstall all the myriad components. Your post led me to the, as you say, “easy” solution. It does indeed seem to work. I know posting stuff doesn’t always bring positive comment, so I want to tell you that I am grateful that you took the time to share your experience in a place where it could be found. Thanks, Dirk

    • 26 March 2024 10:32 am  link

      Thank you for your comment! I’m very happy to hear that it helped you access your file again. It sounds like it’s a very valuable file!
      Something else you might consider trying out is the Mac OS 8 emulator I recently wrote about: https://blog.alexseifert.com/2024/03/17/mac-os-8-as-an-electron-app/. That requires no setup whatsoever. I know it’s Mac OS 8 instead of Mac OS 9, but they were similar, so it may still work. That emulator will also run on multiple platforms: Mac, Windows and Linux.

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