I've seen dozens of terminal commands that will allow High Sierra to put the mac os sierra installer on a USB disk but it won't work for me. Seems like something happened with the installer from 2018 to now. Has anyone found a fix?
Mac Pro, macOS 10.12
The old installers certificate expired recently, so you need to download a newer version.
Click on this link, How to upgrade to macOS Sierra - Apple Support
The instructions are slightly different from before so read Section 4 to Section 7
carefully.
First you will download InstallOS.dmg, and from that you will make InstallOS.pkg
double-clicking on that will open an installer window. At this point the dialogue sounds like it
is about to install the OS, it is not, it is going to create Install macOS Sierra.app in your Applications
folder. It is from that you can create the bootable USB installer.
The old installers certificate expired recently, so you need to download a newer version.
Click on this link, How to upgrade to macOS Sierra - Apple Support
The instructions are slightly different from before so read Section 4 to Section 7
carefully.
First you will download InstallOS.dmg, and from that you will make InstallOS.pkg
double-clicking on that will open an installer window. At this point the dialogue sounds like it
is about to install the OS, it is not, it is going to create Install macOS Sierra.app in your Applications
folder. It is from that you can create the bootable USB installer.
Before you open Terminal and try the createinstallmedia command open Disk Utility and reformat your USB Stick.
If you are on High Sierra click on View in the menubar and select Show All Devices.
Highlight the Disk in the left column, not the indented Volume. click Erase.
Name: MyVolume
Format Mac OS X Extended (Journaled)
Scheme: GUID Partition Map.
see screenshot below
The new Sierra file is not going to work to CREATE the 'createinstallmedia' because there is some kind of bug associated exactly as you describe the error. The work around is to create the bootable media using the old Sierra file; then when completed copy in the new Sierra file.
Hi. THanks for the info but this is basically what Apple says to do which I've tried before and still does not work. I copy/paste the terminal command exactly and i get the same error message. "/Volumes/MyVolume is not a valid volume mount point."
BTW the USB I'm using is called MyVolume.
Still no solution to this issue? I can't believe it's so hard for Apple to fix this, or at least make available the previous installer with the expired certificate so people can built the installer properly.
I'm following you up to installing the .dmg and getting the .pkg and installing but I need info on how to avoid errors when trying to install it onto a USB....
Smokerz echos exactly what I've found online in various forums. I was hoping Apple might have fixed the bug by now. Where can I get an old Sierra file?
Hey there jerbearferrjerr,
Thanks for reaching out to Apple Support Communities. I understand you’re having issues creating a bootable installer for Mac OS X Sierra. I’ll be happy to help with this.
Take a look at this article for the exact command you want to use for Mac OS X Sierra:
How to create a bootable installer for macOS
If that’s not working, see if this works in safe boot or a new user account. This can also isolate and possibly resolve this issue:
Use safe mode to isolate issues with your Mac
How to test an issue in another user account on your Mac
Let me know if this allows you to create the installer.
Cannot get os sierra install to work as a bootable usb disk
