Which classic system software is right for me?

The answer to most technology questions is “it depends” – and this is certainly true for selecting an OS for a classic Mac. Each option comes with pros and cons.

System software 1-5

I personally wouldn’t recommend going here unless you needed to for some reason – such as running a specific old application. Or maybe you’re just curious about these prehistoric pieces of software history. In any case, you’d be better off just checking these out with an emulator like Mini vMac. There are tons of limitations ranging from file system hierarchy limitations to bare-bones general usability.

Pros: Interesting from a historical perspective, very small and can fit on floppies alongside other apps

Cons: Various technical limitations, about as primitive as it gets on Mac

System 6

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Ah, System 6. System 6 was released in the late 80s and was widely used into the 90s, until System 7 was finally released. If you’ve never used it, you may be surprised how different it was, but also how versatile it actually is. On older black & white compact Macs, it’s fast and responsive and can cover most needs.

There are oodles of classic games, desktop accessories, and customization available to System 6. If you’re running a black & white compact Mac like a Plus, SE, Classic, etc it’s a great option.


  • Lightweight and flexible. This is by far the largest pro on the list. System 6 needs less memory and takes up less space. On older systems where resources are limited, it’s a perfect fit.
  • Still able to boot from a floppy and run applications. If the Mac doesn’t have a hard drive – then System 6 is probably your best bet.
  • Needed to run some older software (games in particular)
  • MultiFinder – a unique thing to System 6. MultiFinder, the first multitasking environment for Mac, allows you to decide if you want to run multiple applications at once – or by turning it off, the system can close out of the Finder to give the Application or game the maximum amount of memory possible. It’s nice flexibility for older systems.
  • It can run on Macs with less than 1mb of ram! That might be a deciding factor alone.


  • System Folder is not as organized as later systems – all extensions (INITs), control panels (CDEVs), and preference files are all stored together. If you use System 6 for any length of time, your System Folder will be unorganized very quickly, especially if you’re used to later classic Mac OS.
  • Manual extensions and control panel management. You have to remove or add items to turn them on or off, however there things like “Extension Manager” you can add in to facilitate this.
  • Desktop accessories, sounds, fonts – all require a mover utility to add into the system. This can be a pain.
  • Limited to 2 GB drives, which probably won’t be a problem unless you’re adding a SCSI2SD or a super-large drive to your system.
  • Although System 6 does support color, it’s not great compared to later versions of the system.
  • If you’re used to System 7, OS 8 or 9 – there are usability things you’ll miss. For example, there are no aliases, window shade, and such. The maximize behavior of the window and icon sorting/organization features are not really as strong.

TLDR; System 6 is svelte and has great software available to it – but you may miss some of the niceties from the later Mac OS versions.

System 7 / Mac OS 7, 7.5, & 7.6


System 7 was the primary OS for a long time span in the 90s and probably the era of Macintosh I am most nostalgic for. System 7 was a major overhaul of the Mac OS and introduced literally dozens of new features. System 7 is the last generation that the original compact Macs can run, and the first version that requires over 1 meg of ram and a hard drive.

System 7 actually had 3 distinct generations, so let’s break it down…

7.0, 7.1

The initial release of System 7. These versions run well on older hardware, assuming you have >1 mb of RAM and a hard drive. They are a sweet spot in terms of having the features and compatibility of System 7 while retaining some lightness still. 7.0 can still be booted off a floppy, but barely. You can’t un-mount it and swap disks etc. It runs well on the 68000-based Macs still, but may be noticeably slower than System 6, especially while booting.


7.5 introduced even more features, and as a result is slightly heavier than 7. It’s still a great choice for 040s, 030s… and can still run on older Macs like the SE. I’m pretty partial to 7.5 and don’t have a lot negative to say. I suppose my least favorite feature of 7.5 is the ugly AppleGuide icon in the menu bar, I prefer 7.0’s bubble than the light bulb that replaced it.

There were a few updates (7.5.3, 7.5.5) that introduce bug fixes, a new startup logo (officially adopting the name “Mac OS” for the first time!), and more bug fixes (virtual memory fixes) and native PowerPC code. I run 7.5 on my Color Classic Mystic (alongside OS 8).


The last major update to 7 was 7.6. As you’d probably expect it’s heaver than the previous versions. I prefer 7.5 or even 8.0 over 7.6, but it’s still a fair choice for 040s or early Power Macs.

So overall, let’s talk pros and cons…


  • Faster and more light weight than 8, but still can be supplemented with OS 8 generation tech like OpenTransport, Display Manager, and the 68k runtime enabler.
  • Wide range of compatibility with all classic Mac software ranging from 68k to PPC
  • Lots of usability improvements over 7


  • It’s noticeably heavier than System 6
  • Can be unstable in some instances
  • Still has a lot of black and white leftovers from the earlier OS, and there’s that ugly help icon in 7.5!

Mac OS 8 / Mac OS 8.5


Mac OS 8 is a long story. In a nutshell, Mac OS 8 was originally supposed to be a large re-write of the aging Mac OS, but the project fell apart and was scrapped. Instead, what ended up being released was a set of new features built on top of System 7. Even though we never got “Copland” officially, Mac OS 8 was still a welcome update to the classic Mac OS.

Mac OS 8.1 was the last version to support 68k Macs, as 8.5 and onward required PowerPC systems.


  • Nice looking visually, lots of new features
  • Mutli-threaded Finder, allows you to copy multiple files at once
  • More stable, and can recover from more application failures
  • More PowerPC-native code, but still 68k supported


  • Heavy for a 68k machine – really only runs on 68040 or PPC (although it can be hacked to run SLOWLY on an 030)

Mac OS 9

Mac OS 9 was the last of the classic Mac OS. OS 9 only runs on PowerPC, but for those systems it runs extremely well. OS 9 is what I run on my PowerMac 7600 w/G3. Overall, OS 9 is very stable and performs well on its supported machines. OS 9 is a logical choice for the last pre-iMac PowerPCs.

Other Stuff

Well there are more options of course, in particular A/UX, Apple’s first UNIX-based OS. There are third party options, and it’s even possible to run Linux on 68k Macs. But that’s a story for another time!

For now, I hope this information is useful in selecting which Mac OS to run on your vintage Macs!