Downgrade from MacOS Catalina to Mojave

Question

Downgrade from MacOS Catalina to Mojave

I've previously downgraded successfully from MacOS Catalina to Mojave on my Mid-2012 MBP Retina machine. Since then, I upgrade back to Catalina. For a different reason, I need to revert back to Mojave. I'm following the same steps that I used previously, but when I go into terminal to create a bootable external drive:

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

I receive this error: sudo: /Applications/Install macOS Catalina.app/Contents/Resources/createinstallmedia: command not found

The Install App is located in my Applications folder, and the name of my external drive is 'MyVolume'. I did notice that when I downloaded the installer it said:

"This copy of 'Install MacOS' application is too old to be opened in this version of MacOS". Is the installer corrupt or something?

MacBook Pro 15″, macOS 10.15

Posted on Jan 5, 2021 11:26 AM

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Answer 1

DiZoE

Level 4

3,021 points

Jan 5, 2021 11:51 PM in response to Jonathan Kyle

Hey Jonathan! You did run the command for Mojave right? And not Catalina?

You May have been just typing, but I did notice a few missing back slashes. If that’s not the case:

After giving you the download error, did it allow you to click install anyway? (I’d think it would if you see it in Applications).

I’m not sure if there was a change in Big Sur from Catalina, but I notice now, from the get go, it doesn’t allow the opening of the download of older OS’ just says it’s too old to run here, no option to install anyway, (This was High Sierra, so not sure if different otherwise yet, would like to know).

Anyhow, although this error usually doesn’t coincide with the “Command not found” error if typed right. However, I have noticed that some external drives will just fail while others just work fine, even though both formatted the same, so maybe that’s the case here, maybe not.

Hope all goes well!

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