How to create Catalina installation restore/ boot USB from Catalina installed MacBook?

[uandme72]

The support pages on Apple website gives details of creating a Catalina USB from an OS version lower than Catalina. After I download the Catalina from Mac App Store on Catalina MacBook, it stops saying it cannot upgrade.
How do I create an installation restore/ boot USB from a MacBook Air running Catalina OS.

 

[bogdanw]

Try from Terminal

open "x-apple.systempreferences:com.apple.preferences.softwareupdate?installMajorOSVersion=10.15.4"

It shoud opne System Preferences and ask you if you want to donwload the 10.15.4 installer, from which you can create a bootable USB

 

[uandme72]

Try from Terminal

open "x-apple.systempreferences:com.apple.preferences.softwareupdate?installMajorOSVersion=10.15.4"

It shoud opne System Preferences and ask you if you want to donwload the 10.15.4 installer, from which you can create a bootable USB

It downloads, but then says error as you find upon download from Mac App Store..

 

[bogdanw]

It downloads, but then says error as you find upon download from Mac App Store..

If the full installer (~8.17 GB) was downloaded in Applications you can use the 'createinstallmedia' command in Terminal https://support.apple.com/HT201372

 

[ssn637]

I created a flash disk macOS Catalina 15.4 installer via the createinstallmedia command but was unable to perform a clean installation on my MBP 16", which I found strange since every other time a new version of Catalina has been released I was able to wipe the drive and install the newest release via a USB stick that had been prepared with the downloaded installer package.

This time around, as soon as the system completed booting from the flash disk, a pop up message claimed that the version of macOS on the associated disk needed to be upgraded, which I'd never seen before. When I erased the system drive and tried to install macOS anyway, the application began downloading from Apple's servers and I was told the installation would take an hour, so I canceled it and restored from a backup before updating to 15.4 via the Software Update utility.

I'll try again when macOS Catalina 15.5 has been released, or if I note that 15.4 from Apple's Update Server has been updated from the current version (24 March 2020). Funny thing is, I used the same USB Flash Disk to perform a clean installation on my 2018 MBP 13" without issue, so it must have something to do with the 16" models.