Issues - create a bootable installer for macOS

How do you create a bootable installer fo… - Apple Community

Specific Instructions on creating a Bootable Installer of OS X Sierra

ALL CREDIT to Eau Rouge

" The reason that Sierra does not appear in the How to Create A Bootable installer article is Apple pulled it

because they made a mistake when they updated the certificates for macOS Sierra after they expired in October 2019.

Although installing macOS Sierra from the revised version of the Install macOS Sierra.app would work if you tried to create a bootable installer you would get an error from Terminal that Volumes/<USBname> is not a valid mount point.

Apple haven't bothered correcting the issue, but instead removed any advice from their article.

macOS Sierra is still available for download, it is not necessary to make a bootable USB in order to install macOS Sierra.

Click on this link to get macOS Sierra,

How to get old versions of macOS - Apple Support

Go to Use Safari to download macOS to your mac.

Click on macOS Sierra, this will download InstallOS.dmg to your Downloads page.

Once downloaded open the Install.dmg to get the InstallOS.pkg.

Double click on that and you will see an Installation window, this does not install macOS Sierra but

creates the Install macOS Sierra.app in your Applications folder.

(If asked to select a destination for the 'install' make sure you select the Disk your mac is booted to

not any other internal or external disk that you may want to install Sierra on, that is for later.)

Double-click on the Install macOS.app to begin the installation of macOS Sierra.

If you would still like to create a bootable USB installer for macOS Sierra it is possible with this workaround.

As said there is a problem with making a bootable USB installer with the Install macOS Sierra.app

where it returns an error Volumes/<USBname> is not a valid mount point.

To get past this error follow the instructions below.

With Install macOS Sierra.app in your Applications folder open Terminal.

Paste in this command

sudo plutil -replace CFBundleShortVersionString -string "12.6.03" /Applications/Install\ macOS\ Sierra.app/Contents/Info.plist

press return
enter your password
press return

now paste in the createinstallmedia command for Sierra where MyVolume can be replaced with the name of your USB stick

If your USB name has more than one word separated by spaces you would need to type it in as
/The\ USB\ Name


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

press return 
follow the prompts

The process takes around 30 minutes to complete, be patient, Terminal will look like it is not
doing anything but it is.

When ready boot to the USB by Restarting your mac while pressing and holding down the option/ alt key.
After a couple of minutes you will see the Boot Manager, select the USB and press Return.
The mac will now restart to the USB after a minute or two you will see the Utilities panel select
Install OS press Continue.
The installation process will begin, follow the onscreen prompts.              
            

In all of the Terminal commands Apple supplies on the linked page, the bolded, underlined text I marked next is only a placeholder. I grabbed Monterey for an example:

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

You need to change MyVolume to the name of the USB stick you're going to run this command on. I always first name the USB drive something extremely simple. Usually just the letter a. Then the command becomes:

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

You’re showing commands specific to Sierra, and while referencing High Sierra and Monterey.

You’re trying to create a bootable partition, and that’s not something that the Apple tool documents.

What to do? Use a removable storage device (that can be wiped), and create the {version} installer there.

Given its age and its issues, and given anything that can run Sierra can run High Sierra, I would not suggest Sierra.

It is possible to target a partition when creating a bootable macOS USB installer. I have multiple macOS installers on a single drive.

FYI, the macOS 10.12 Sierra installer is (or at least was) broken when it came to creating a bootable USB installer. There is a simple one character edit which needs (or needed) to be done for the Apple command to work, but I don't recall the specifics right now. I don't recall the error it produced without the fix applied, but it may have been invalid mount point. There are some old posts on this forum from about five years ago which tell how to fix the Sierra installer since Apple could never be bothered to edit the single character necessary...so Apple just removed reference to the installer from some of the documentation. I can try to look for the information later if I can remember when I have more time.

Is there a reason you are not going for macOS 10.13 High Sierra?

From memory @Eau Rouge was the go to for the OS X Bootable Installer issue

Quick Filtered Search as per below

https://discussions.apple.com/search?q=os%20x%20sierra%20bootab%20USB&requestId=63da155ddef6458d74ee5376df4a5b4a%2C%20abdaa696eea8cdc7f3e674a4e237a344&searchId=2i_PAGgHSa6V1_QbBRPDZA&page=1&content=filterDiscussions&source=aml&origin=asc_serp&author=61a79445f74f7314

I don’t know if it’s possible to write the installer to a volume. I do not think so.

The instructions say it should be macOS extended, so an APFS Volume would likely confuse it. I have created a USB installer on a partition of a drive, but it isn’t really designed for that.

Creating a Bootable Installer is possible for High Sierra macOS 10.13.

But your command appears to be trying to create a bootable Installer of Sierra OSX 10.12

Q - " sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ Sierra.app "

Apple Create Bootable Installer is not listing a Specific Terminal Command for OS X 10.12 Sierra

To be honest - I no longer have a working copy of the Terminal Command

Perhaps another Contributor can assist Here

FWIW, I've only used USB flash drives. They always worked.

Good point especially and unless Apple Updated the Apple Certificate within the DMG of Sierra OS 10.12

@P. Phillips, Thanks for the search. I also posted those instructions a few times as well, but haven't had to access them for a while.