How to create bootable installer

Have finally got it all working at the end but it certianly wasn't easy including having to read/post in many other forum threads to get to the bottom.

Some hurdles on the way that wasn't explicitly clear in Apple's official isntructions:

• If you are on a newer MacOS you are not able to download older MacOSs from the APP store. So you can only use the browser download option to download a .pkg version of earlier versions.

• If you are on a newer MacOS you are not able to unpack the .pkg into the Applications folder. So you need to find a Mac running a older MacOS to unpack that .pkg file into the Applications folder.

The above 2 steps makes it difficult because it means if you are trying to revive a old iMac by creating a bootable installer, you first need access to another working iMac running a old MacOS to be able to create that comptable installer.

• (I was stuck on this for a long time) If you have downloaded Sierra, you have to run a terminal script so that it think it's runing verseion 10.12.3 instead of the 10.12.6 it downloads as. If you skip this step you won't be able to copy the installer onto your external drive.

• You also have to Erase your main drive clean as Mac Extended Journal or you will run into the installation error in my previous post.

Hope the above helps anyone else that's trying to do the same.

Hi Jack, thanks for the reply.

That is what I have been doing but the installation gets stuck "-399 (or another number) seconds remaining", even if I leave it for hours.

Forgot to clarify that I have other Mac machines avaliable that I can use to create a bootable installer, I just like to know the steps on how to do that.

Thanks

I managee to follow online guides and got the last part with the below error in terminal. Anyone know what the error message is refering to? Maybe because I am trying to copy the installer to a SSD volume instead of a USB flash volume that is causing the below error?

Last login: Sun Sep 10 19:38:32 on ttys000

Chads-iMac:~ ChadHsieh$ sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/SamsungSSD 

Password:

Usage: createinstallmedia --volume <path to volume to convert> --applicationpath <path to Install macOS Sierra.app> [--force]

Arguments--volume, A path to a volume that can be unmounted and erased to create the install media.

--applicationpath, A path to copy of the OS installer application to create the bootable media from.

--nointeraction, Erase the disk pointed to by volume without prompting for confirmation.

Example: createinstallmedia --volume /Volumes/Untitled --applicationpath "/Applications/Install macOS Sierra.app"

Chads-iMac:~ ChadHsieh$ 

There is no issues getting into the installer screen to start the install. It's just it gets stuck.

I've read elsewhere people had similar issues and resolved it with installaing from bootable installer.

I'm just having issuing with that process as per above.

Have succesfully created the bootable isntaller and after booting from it and running the installer sucesfully the Mac restarts itself and I get the error message below:

Any advise on what is causing this and what I should try? Thanks in addvance once again.