Updating or reverting MacOS on a 2020 Intel iMac
Updating or reverting MacOS on a 2020 Intel iMac
At work, we must revert the operating system on a few new iMacs bought recently. These are late 2020 Intel i7 models with 27-inch displays, which are solid hardware but need an older OS to function properly on some servers. This isn’t something we can skip—it’s a necessity. Earlier iMacs were simpler to handle, but these newer ones are proving challenging. Anyone have experience with this process? (I rarely deal with Mac support, but I’m facing it now.) Thanks!
Which macOS version is required? Catalina remains the only supported release for older machines, meaning you can't upgrade to newer versions directly. If your system needs an earlier OS like Mojave or High Sierra, options such as Parallels Desktop or VMware Fusion can help run those versions in a virtual environment. These tools provide a workaround, though they aren't ideal. The 2020 27" iMac is limited to Catalina, Big Sur, Monterey, and Ventura at this time—older releases won't run natively.
During startup, the macOS Recovery process selects various versions of macOS based on your system. Pressing Shift-Option-Cmd-R can choose the version that came with your Mac or the nearest available one. For more details, visit Apple Support.
I haven't checked it, but I'm not confident it would be effective. Even if it were, it wouldn't be suitable for a production setting like you described. VMware Fusion or Parallels Desktop are the only viable choices besides purchasing a newer iMac that supports Mojave.
they're making progress, but it's not enough right now. Suppliers are taking their time, so I wouldn't be overly hopeful about 'this year'