How to make a bootable macOS High Sierra install disk on USB or Thunderbolt drive
If you don't have a macOS Server installation and have multiple macs to upgrade, it can be a bandwidth-sucking chore. Instead, there's a way to download a full install of the latest version of High Sierra and make install media using the Terminal -- AppleInsider shows you how.
If you only manage one Mac, you really don't need to do this, unless you want a local copy on hand form some reason. If you still want to get started, download macOS from the Mac App Store.
The installer will launch automatically after download. Quit the installer without installing High Sierra.
After downloading the installer, mount the volume you want to use to make the bootable installer. Your best bet is something fast, like an external SSD, or fast flash drive -- the speed of your installs will vary greatly based on the speed of your media on both ends of the install.
For the purposes of this tip, in the Finder name the external drive macinstall.
In the Utilities folder, open the Terminal.
Enter:
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/macinstall and hit Return.
The Terminal will request your administrator password, so enter it to validate and hit Return.
Confirm the external volume erase, rename, and copy, by hitting Y and hit Return when prompted.
When the Terminal informs you that the process is done, you should have bootable media which can be used on any compatible Mac. This works with nearly all media -- but we've found that some cheap USB 3.0 flash drives won't boot, and there is no solution other than using a different drive.
If you do have a macOS Server installation, you can cache upgrade files on the server to only download them once. How to use macOS Server to do that is a tip for another day.
If you only manage one Mac, you really don't need to do this, unless you want a local copy on hand form some reason. If you still want to get started, download macOS from the Mac App Store.
The installer will launch automatically after download. Quit the installer without installing High Sierra.
After downloading the installer, mount the volume you want to use to make the bootable installer. Your best bet is something fast, like an external SSD, or fast flash drive -- the speed of your installs will vary greatly based on the speed of your media on both ends of the install.
For the purposes of this tip, in the Finder name the external drive macinstall.
In the Utilities folder, open the Terminal.
Enter:
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/macinstall and hit Return.
The Terminal will request your administrator password, so enter it to validate and hit Return.
Confirm the external volume erase, rename, and copy, by hitting Y and hit Return when prompted.
When the Terminal informs you that the process is done, you should have bootable media which can be used on any compatible Mac. This works with nearly all media -- but we've found that some cheap USB 3.0 flash drives won't boot, and there is no solution other than using a different drive.
If you do have a macOS Server installation, you can cache upgrade files on the server to only download them once. How to use macOS Server to do that is a tip for another day.
Comments
I remember when it was a lot more work to create a bootable drive. Still, a GUI option would be a nice option built into the installer to help that may need to help others over the phone,
Will this work from a read-only volume like a DL DVD-RW? I'm considering testing High Sierra on an external drive to see if I want to upgrade to it on my iMac now that El Capitan is abandoned by Apple on Logic X 10.4.
https://sqwarq.com/boot-buddy/
sqwarq is Phil Stokes' site for his troubleshooting software. He's well known in the ASC (Apple Support Community) for helping users troubleshoot their system issues.
Now that I think about it, another reason why I suggested that you would have to “bug” Apple Support is because at one point I called them and I was specifically told that the Sierra installer was no longer available. I explained that it couldn’t be the case because some people can’t upgrade to High Sierra yet due to compatibility issues. The tech support rep’s response was basically that those people are out of luck, because the Sierra installer was no longer available, so I hung up. At that point I thought that Apple was intentionally pushing people to upgrade to High Sierra and that I would have to plead my case for a Sierra installer. So I called Apple Support again and spoke with a rep that was much more understanding. After I explained my situation, she emailed me the direct link to the Sierra installer. So based on my experience it seemed to me that Apple did not want to make the Sierra installer readily available, but if you “bugged” Apple Support and pleaded your case they would make it available to you. I did not necessarily think it was a bad link that needed to be fixed. So if the link to the Sierra installer is now working properly, terrific. Again, I was just trying to be helpful.
Most likely because they updated it to work properly.