JAjasomill·Dec 14, 2024
Not really difficult to reinstall every major Intel Mac OS release, at least, as they're all downloadable from Apple in one way or another:
1. You can reinstall "the version of macOS that came with your Mac or the closest version that’s still available" via Internet Recovery[1].
2. You can download installers for every major release back to High Sierra from Apple via the App Store[2] or directly from Apple's update servers using a tool like installinstallmacos[3].
3. You can download installers for Sierra, El Capitan, Yosemite, Mountain Lion, and Lion directly from the Apple support site[2].
3. You can download Snow Leopard and Leopard from the Apple developer site[4] (free registration required; paid membership possibly required).
Note that the downloads on the developer site are the 10.x.0 retail builds, which may not be compatible with
Read the rest
all Macs that shipped with a later build.
In this case, assuming the version you need is no longer available via Internet Recovery, you'll probably need to install and patch on an older machine, then transfer the patched install to the target via disk swapping, imaging, or NetInstall, or to install and patch directly to the target machine's hard drive using Target Disk Mode (or else track down a copy of the model-specific restore DVDs that shipped with the target).
Downloads from the App Store and support site should always be the latest point release, so this should only be a problem if you want to install Snow Leopard or Leopard on a post-release machine.
Installing non-final point releases is admittedly problematic: you can download some but not all x.y.0 builds from the developer site, some but not all patches from the support site, and a few x.y.(z < latest) installers from Apple update servers, but AFAIK there's no way to get an arbitrary point release of any version unless you can find someone who has a copy saved.
Though I wouldn't even be a little surprised if older patch releases were still available, unadvertised, somewhere on some public Apple Web server, given that you can still download System 6.0.3 (released October 1990; last supported Mac was the Classic, discontinued September 1992) if you know the correct URLs[5].
[1] https://support.apple.com/guide/mac-help/use-macos-recovery-...
[2] https://support.apple.com/en-us/102662
[3] https://github.com/munki/macadmin-scripts
[4] https://developer.apple.com/download/all/
[5] http://download.info.apple.com/Apple_Support_Area/Apple_Soft...
http://download.info.apple.com/Apple_Support_Area/Apple_Soft...
http://download.info.apple.com/Apple_Support_Area/Apple_Soft...
http://download.info.apple.com/Apple_Support_Area/Apple_Soft...