What should always work is creating a bootable installer and booting from that to perform the installation.įor many M1 Macs, this isn’t exactly convenient. Normally, installers still work between minor versions, though, so you should still be able to run the 11.4 installer if your Mac is now running 11.5.2, although even that isn’t guaranteed. If you try, you’ll get a misleading error. If you’re already running a beta-release of 12 and want to install any version of Big Sur, then you can’t simply run the installer app. Now’s the time to ensure that you have the set you require before Apple starts thinning the list.įor a long time now, Apple’s installers can only open and install the current and newer major versions of macOS. Mr Macintosh provides links for all full installers available from 11.2.3 onwards.

If you didn’t download and keep an installer for 11.1, for example, you won’t find one on Apple’s servers.Īlthough Apple currently makes installers available via softwareupdate from 11.3.1 onwards (use softwareupdate -list-full-installers to check), once 12.0 has been added to that list, it’s likely to remove older versions of Big Sur, perhaps leaving just 11.5 and later. If you do want to keep Big Sur available to your M1 Mac, now’s the time to start.Įarly versions of Big Sur came and disappeared all too quickly: as soon as Apple released the next, it removed the installer for the previous. These days, downgrading macOS can be a long and painful task. You might be a developer, security researcher, or just want to ensure that you don’t burn your boats. Marvellous though Monterey should be, many of us need to retain access to Big Sur and earlier versions of macOS after we’ve upgraded in a few weeks time.

Upgrade m1 mac mini