My good old MacBook Pro from 2011 can only supports macOS up until 10.13 High Sierra. It’s been purring along nicely with macOS 10.12 Sierra for the last couple of years, and I didn’t see the need to upgrade just yet. Why risk breaking things that are working, right?
A couple of weeks ago, macOS 10.14 Mojave was released, with which my MacBook is sadly no longer compatible (not officially at least). So when I searched for “High Sierra” on the Mac App store, I was surprised to learn that it didn’t come up. It appears that only the very latest macOS release is available to download from the Mac App Store.
So now the $100k question is: How can I get an official copy of macOS High Sierra, now that Mojave is out? I’ve never downloaded it before, therefore it doesn’t show up in my “previous purchases” tab either. Have I missed my 12 month window to download the last operating system that’s compatible with my hardware?
Lucky for us, Apple have made some contingencies. I did some research and found several older Mac operating system for ya’ll’s enjoyment. Might come in handy 
Mojave
We can get macOS 10.14 Mojave via these links:
- Apple’s Instructions: https://support.apple.com/en-us/HT201475
- Direct Link to Mojave on the Mac App Store
High Sierra
We can get macOS 10.13 High Sierra via the following links:
- Apple’s Instructions: https://support.apple.com/en-us/HT208969
- Direct Link to High Sierra on the Mac App Store
Sierra
We can get macOS 10.12 Sierra via the following links:
- Apple’s Instructions: https://support.apple.com/en-us/HT208202
- Direct Link to Sierra on the Mac App Store
El Capitan
We can get macOS 10.11 Sierra via the following links:
- Apple’s Instructions: https://support.apple.com/en-us/HT206886
- Direct Link to Sierra on the Mac App Store
Yosemite
Apple even have an article on how to get older versions of Mac OS onto Yosemite (not available on the US site).
- Apple’s Instructions: https://www.apple.com/uk/support/osx/upgrade/
Snow Leopard
Mac OS 10.6 Snow Leopard, “The world’s most advanced operating system”, was never available as a download. But as of 2018, we can still buy a set of install disks from Apple for $19.99. This was an important release for many reasons, one of which was the inclusion of the Mac App Store, through which subsequent operating systems were distributed.
Also available on disks from Apple:
- Mac OS 10.7 Lion: https://www.apple.com/shop/product/D6106Z/A/os-x-lion
- Mac OS 10.8 Mountain Lion: https://www.apple.com/shop/product/D6377Z/A/os-x-mountain-lion