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Recover installation files from older versions of macOS to easily restore your Mac or resurrect an old Apple computer.
It is generally when reinstalling macOS that you want to get your hands on the system installation file corresponding to your machine. If finding the installation image of a recent version of macOS is quite simple when it is in the Mac App Store, this is unfortunately not the case for all iterations of macOS.
If you’ve already downloaded older versions of macOS from the Mac App Store, you should be able to find them fairly easily in your purchase history to download again. On the other hand, if you haven’t already downloaded all older versions of macOS, some may not be offered to you if you search for them in the Mac App Store. However, they remain accessible, provided, of course, that you have the direct access link.
Anyway, there are several possibilities to recover macOS installation images, both for the most recent versions like Monterey or Big Sur, as well as for older versions. You can either go through the Mac App Store or Apple’s support pages, or use a third-party utility that will retrieve the installation files for the different versions of macOS.
Download older versions of macOS from Apple
To retrieve installation files from older versions of macOS, you can perfectly use the official channel, i.e. Apple. With the exception of Mac OS X Lion and Mac OS X Mountain Lion which are available for direct download from the pages Apple Support, newer versions of macOS are still available on the Mac App Store. If you can’t find them by typing their name in Apple’s app store search engine, you can access them from their direct link.
Be careful however, you will absolutely have to consult the Mac App Store from a machine compatible with the desired version of macOS to be able to download the installation file.
Download macOS Monterey (Free)
Download macOS Big Sur (Free)
Download macOS Catalina (Free)
Download macOS Mojave (Free)
Download macOS High Sierra (Free)
Download macOS Sierra (Free)
Download macOS El Capitan (Free)
Download Mac OS X Mountain Lion (Free)
Download Mac OS X Lion (Free)
Download older versions of macOS with MIST
It is not mandatory to go through the Mac App Store or Apple’s support pages to download installation files for older versions of macOS. It is indeed possible to recover them very easily using a third-party tool, MIST, which is responsible for automatically recovering the installation files from Apple’s servers.

Download MIST for macOS (Free)
Once MIST is installed and running on your Mac, it automatically lists recoverable macOS versions. You will be able to download the versions of macOS Monterey and macOS Big Sur (for Macs equipped with an Apple M1, M2 processor, etc.), or recover the complete installers for macOS Monterey, macOS Big Sur, macOS Catalina, macOS Mojave, and macOS High Sierra.

The main advantage is that you can grab the update of your choice for each version of macOS, unlike the Mac App Store which offers the latest updated version. The icing on the cake, MIST even gives you the choice of the type of file to recover. You can opt for an installer in application, disk image, ISO, or Package format.
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