[This section is still work in progress]
It seems that in the new Mojave App Store, the old installers purchased do not appear at all. The "simple method" of entering the history of your purchases is no longer valid.
Sierra and High Sierra are available via direct links – see below.
Test the installation program of El Capitan that has a published URL will appear in the App Store, but if the download is requested, the message "Not valid for this Mac" will not appear plus, it now says "The requested version of macOS is not available".
Additional tests are needed – welcome contributions – to see if other versions of the operating system are removed in the same way. We may need direct links to these, which I do not have at the moment.
Sierra itself has now disappeared from everyone's buying history. However, Apple keeps full Sierra availability even if High Sierra is absent. No Apple ID is required.
High Sierra Link tested by Mojave in January 2019 – still works for download, though via the new Software Update control panel. It will not work on a Mac Mojave, but you will have the installer in your Apps folder to move it somewhere else.
I've successfully tested this method in January 2019 – still working as shown for a Mac limited to El Capitan. Old purchased operating systems are always listed and accessible.
The easiest way – if available – to use your purchase history on the App Store.
If you have previously installed an OS X version, it will still be available in this list. This should include all public beta versions.
The version available from this list will always be the latest version of its type, namely 10.7.5, 10.8.6 … 10.11.6
Image heavily modified to display only operating system versions.
Note that the download or installation will be based on whether or not you have saved the installation file locally, even on a non-bootable drive.
If the version you are trying to download is older than the Mac you are trying to download, the download is not allowed.
[looking for workarounds to this part – edits welcome – I can’t test this as the newest Mac I have is a 2012 Mac Pro]
Potential workarounds, need for testing –
How to re-download Lion from Mountain Lion
If you are trying to upgrade an older machine running Snow Leopard or Lion, you can get a special version of El Capitan on the App Store.
This version of El Capitan is for users of OS X Snow Leopard or
OS X Lion who wants to upgrade to macOS High Sierra. If you are
running Snow Leopard or Lion and wants to move to High Sierra,
you must first install El Capitan. This version of El Capitan can
also be installed on computers that are not compatible with High
Note this last sentence … this version will not be installed on a machine that is do not currently on Snow Leopard or Lion, if the machine is able to run High Sierra.
This makes it a very specific resource and not a general "get out of prison" card for anyone who wants El Capitan.
If you need to reinstall from Recovery and previously used Sierra 10.12.4 or higher, 3 options are now available.
Hold the appropriate key combination to the start chime …
- cmd R
reinstall the latest macOS installed on your Mac without upgrading to a later version
- Opt ⌥ cmd R
upgrade to the latest Mac OS compatible with your Mac
- shift Opt ⌥ cmd R
reinstall the macOS that came with your Mac or the version closest to it that is still available.
The first two options are available for all newer Macs than Lion, around 2009.
There is also the option to create a bootable USB flash disk drive, using this Apple tool – Apple KB: OS X: About the Recovery Disk Wizard
If you have access to an earlier version of any operating system, 10.11.0, etc., and want to upgrade, you can download Apple's Combo Updaters which contains everything needed to directly access the latest version of the point in one step, for example. 10.11.6
Google is good at finding them, like the best result if you simply do a search
combo update 10.11 but here are links to some
El Capitan 10.11.6
High Sierra 10.13.6
If you need to create a bootable USB stick to install from
How to create a bootable USB flash drive on a Mac?
How to create a bootable USB drive Mac on Windows?
Find a friend who can access the download[[[[advisable]
Find a torrent / sharing site[[[[not recommended]
There is no "legitimate" way to download macOS from a computer other than Mac. It requires the Apple App Store.
Note: You can not use a Time Machine backup to return to an older operating system than the last backup on that Time Machine drive.
This means that to preserve your ability to restore to a previous backup and operating system with your Time Machine backup, you must swap this Time Machine drive before you upgrade the operating system. Indeed, once the Time Machine reader sees the new operating system, it is no longer possible to return to the old one. You can still manually extract data from Time Machine, but you can not use them to restore the older operating system.