Complete step-by-step instructions for installing a new copy of macOS to an external disk, making it bootable. For Intel and M1 Macs of all flavours.
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Why would you want to go to the lengths of erasing your startup disk and installing a macOS upgrade clean? Here’s why, and how to do it.
Install macOS in Recovery can only install one version, which probably isn’t the one you want. How can you get an earlier version installed, then?
Snapshots are designed to make it easy to roll back to a previous state. Why then can’t you use a snapshot to roll back to an earlier version of Big Sur?
For some, inability to clone to the internal SSD of an M1 Mac seems disastrous. In reality, it could achieve little, and there are better solutions.
How to install macOS on your M1 Mac’s external SSD. But it comes with a snag: you can only install 11.2 and can’t update it to 11.2.1.
It’s a commonplace task: make a bootable external disk for emergency use, containing your diagnostic and repair tools. On a new M1 Mac? Should be simple.
If you haven’t upgraded to Big Sur yet but intend doing so early, be reassured: it’s one of the smoothest for years. Full details and a few tips to help.
Older versions of Catalina can fail to erase the System and Data volumes, but 10.15.6 should be able to, making clean re-installation simpler.
Follow Apple’s instructions for a clean re-install, and you’ll probably hit an error, and be left floundering in Recovery mode with an unbootable system.
