How to install Monterey on an older iMac?

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How to install Monterey on an older iMac?

I have a 2017 iMac booted from a Samsung T7 SSD. Works great. I erased the iMac Fusion drive, but now need to install an earlier version of Mac OS on it (for one lousy piece of software). I want to install Mac OS Monterey, but when I try to use the App Store, it goes to Settings, and downloads as if I'm going to downgrade my OS.

How can I get it to just download, so I can then reinstall it on my old fusion drive inside the iMac?

Thanks

iMac 21.5″, macOS 10.13

Posted on Jun 2, 2023 3:44 PM

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Answer 1

Top-ranking reply

dialabrain

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Jun 2, 2023 4:51 PM in response to Jeff Jay

FWIW, you can't run the Monterey installer from Ventura. You have to create a USB bootable installer of Monterey, boot your Mac with it, then select your Fusion drive to install it.

Create a bootable installer for macOS - Apple Support

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Answer 2

dialabrain

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Jun 2, 2023 4:20 PM in response to Jeff Jay

Run this command in the Terminal

softwareupdate --fetch-full-installer --full-installer-version 12.6.6

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Answer 3

Jeff Jay Author

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Jun 2, 2023 5:09 PM in response to dialabrain

The link you provided gave me a different command to use in terminal:

sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

That did the trick.

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Answer 4

Jeff Jay Author

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Jun 2, 2023 5:26 PM in response to dialabrain

When I put that command in Terminal, as per the page you referenced about how to create a bootable installer, all I had to do was chage MyVolume at the end to the name of my external drive. It then erased the external drive, and made it "Install macOS Monterey," --a bootable installer. I can now use that to install Monterey on my iMac's old fusion drive. So, the link you gave me on how to create a bootable installer gave me the correct instructions.

Thanks!

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Answer 5

dialabrain

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Jun 2, 2023 5:51 PM in response to Jeff Jay

Jeff Jay wrote:

How can I get it to just download, so I can then reinstall it on my old fusion drive inside the iMac?

FWIW, I thought you were having a problem with downloading "Install macOS Monterey". Apparently you already had it.

In any case. Glad it worked out.

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Answer 6

Jeff Jay Author

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Jun 2, 2023 4:28 PM in response to dialabrain

Thanks

When I ran that command, I got a message in a pop-up window saying it couldn't be installed over Ventura. I just want to download an installer, and install on the old fusion drive.

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Answer 7

dialabrain

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Jun 2, 2023 4:43 PM in response to Jeff Jay

You're welcome. You got that message before it downloaded?

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Answer 8

Jeff Jay Author

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Jun 2, 2023 4:52 PM in response to dialabrain

No, it would not download. Even from terminal! Instead, I got a message in a pop-up window saying it couldn't be installed over Ventura. It never downloaded. I got the message in a matter of seconds.

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