How to install macOS 14 Sonoma or 13 Ventura on an external partition

Question

Created Jun ’23

Replies 4

Boosts 2

Views 3.6k

Participants 4

I would like to install macOS 14 Sonoma on an external partition, but I couldn't find an installer on the developer website. It seems that it's only possible to upgrade from the System Settings, so I thought I would install Ventura first on the separate partition and then upgrade to Sonoma.

I downloaded the Ventura installer from the App Store and selected the external partition during the installation, but when the Mac reboots, it just reboots into my main macOS partition. If I shut down and hold the power button pressed to select the boot partition (I have a M1 MacBook Pro 14" 2022), then nothing happens: an indeterminate progress indicator spins for a couple seconds, the partition list remains there and I can only successfully boot into my main partition again. I also tried running the installer from another macOS Ventura and macOS Monterey partition I had installed last year, but when I select the partition on which to install the new Ventura, nothing happens and I can only quit the installer.

Is there a way to debug all these issues? How can I install macOS Sonoma on a separate partition without overwriting my main macOS Ventura install?

Boost

Answer 1

endecotp OP

Jun ’23

I would like to install macOS 14 Sonoma on an external partition

Me too!

I couldn't find an installer on the developer website.

I downloaded the .ipsw "restore image" from https://developer.apple.com/download/ but I don't know what to do with it!

In Disk Utility I can select my external disk and click "restore", and there is an "image" button, but the .ipsw file is not selectable in the file picker.

Is this one of those things where you have to hold down shift while clicking a button and a load of extra choices appear?

Someone must know how to do this....

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Answer 2

Odysseus42 OP

Jun ’23

I have the same exact issue. I called Apple support, but they ended up telling me that it's not a supported configuration and if it doesn't work there is nothing else they can do. It's very unfortunate. This worked fine on my Intel Macbook Pro. I hope it's just a bug in Ventura and it will get patched. Annoyingly, we can no longer even install a previous macOS version, and even if we do get an older macOS version, it won't boot on an Apple CPU mac with a newer macOS version. How are folks testing different macOS versions? Do you have to get several macs now?

https://discussions.apple.com/thread/254921596

2

Answer 3

Nickkk OP

Jun ’23

Did you just download the Ventura installer and ran it? Because as I wrote in the original post, I wasn't able to install Ventura either.

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Answer 4

Odysseus42 OP

Jun ’23

I was doing installs from the Ventura download and the recovery partition. My last attempt was via the recovery partition. I can’t see why it would matter, but this certainly seems like a bug, so who knows

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