Yes, I found

Download macOS High Sierra for offline install [duplicate]


macOS High Sierra media installer

but they don't fit my use-case. I need to update a number of Macs to High Sierra to address Spectre/Meltdown ASAP, and the questions linked above had to do with the High Sierra beta.

So: how do I download macOS High Sierra for offline installs?


Answering my own question:

From the App Store, grab the High Sierra installer. It will launch "Install macOS High Sierra" after the download completes. Click "Continue", accept the licensing agreement, select the install drive, then the installer will prompt for an admin password. After that, it will begin downloading to "/macOS Install Data" on the local machine.

The main data file is

/macOS Install Data/InstallESDDmg.pkg

When the download is complete, the installer will prompt for a system restart. Before doing that, inspect the download directory:

sudo find /macOS\ Install\ Data  -type f -exec ls -l {} \;
-rw-r--r-- 1 user staff 328        Dec  4 19:03 '/macOS Install Data/AppleDiagnostics.chunklist'
-rw-r--r-- 1 user staff 2613173    Dec  4 19:03 '/macOS Install Data/AppleDiagnostics.dmg'
-rw-r--r-- 1 user staff 1948       Dec  4 19:03 '/macOS Install Data/BaseSystem.chunklist'
-rw-r--r-- 1 user staff 478740408  Dec  4 19:04 '/macOS Install Data/BaseSystem.dmg'
-rw-r--r-- 1 user staff 2124       Jan  8 08:39 '/macOS Install Data/index.sproduct'
-rw-r--r-- 1 user staff 4706541399 Dec  4 19:09 '/macOS Install Data/InstallESDDmg.pkg'
-rw-r--r-- 2 user wheel 1584       Dec  4 19:09 '/macOS Install Data/InstallInfo.plist'
-rw-r--r-- 1 root wheel 893        Jan  8 07:38 '/macOS Install Data/Locked Files/.disk_label'
-rw-r--r-- 1 root wheel 15         Jan  8 07:38 '/macOS Install Data/Locked Files/.disk_label.contentDetails'
-rw-r--r-- 1 root wheel 3557       Jan  8 07:38 '/macOS Install Data/Locked Files/.disk_label_2x'
-rwxr-xr-x 1 root wheel 23520      Dec  1 12:37 '/macOS Install Data/Locked Files/cleanup_installer'
-rw-r--r-- 1 user staff 269647     May 17  2017 '/macOS Install Data/OSX_10_13_IncompatibleAppList.pkg'

Then, copy the download directory off to another machine for future use.

  • 1
    Or use one local mac as a iCloud/MAS cache and have the rest download off of that one. – John Keates Jan 10 '18 at 0:26
  • How did you achieve the last part? I tried this on 10.10.5 upgrading to macOS High Sierra: 1) download files on computer A 2) copy files to computer B 3) run installer on B, but this deletes the copied files and the installer starts over downloading the files. Any ideas? – Tim May 5 '18 at 7:31
  • You might want to look into netboot serving. Makes life so much easier. – l008com May 5 '18 at 8:35

If you go ahead and run the 19MB installer (/Applications/Install macOS High Sierra), it will download the remaining install files and place them under /macOS Install Data. Simply abort the install when it asks which disk you want to install to.

To restore the ability to create install media, do the following: Open Terminal and run: sudo -s Enter admin credentials to gain root access and cut-n-paste the following 3 commands

mkdir /Applications/Install\ macOS\ High\ Sierra.app/Contents/SharedSupport
cd /macOS\ Install\ Data
find . -mount | cpio -pvdm /Applications/Install\ macOS\ High\ Sierra.app/Contents/SharedSupport

You can now use the normal createinstallmedia command:

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

I had a similar issue, but the above solution did not work for me. I'm still looking for a solution to upgrade to macOS High Sierra using previously downloaded install files.

I thought I found a solution below, but this also did not work.

Re-use install files on identical Macs (maybe)

This did not work for me, the installer complained about corrupt/bad install files after restarting. Perhaps this is because the install files were downloaded on 10.9 and I was trying to install them on 10.10 - so it might work for you

  1. Get macOS install files on a computer
    1. Use the App store (recommended)
      1. Download 'Install macOS High Sierra.app' from App Store
      2. Run installer, which downloads installer files, stop installer when it asks to restart
      3. The files are now located in /macOS\ Install\ Data
    2. Download files manually
      1. See https://github.com/Jinsung-L/install-macos-high-sierra
      2. See https://www.insanelymac.com/forum/topic/329828-making-a-bootable-high-sierra-usb-installer-entirely-from-scratch-in-windows-or-linux-mint-without-access-to-mac-or-app-store-installerapp/
      3. See https://7labs.io/tips-tricks/macos-high-sierra-direct-download.html
      4. Problem: I'm not sure how to choose which InstallESD to download, this post might help https://apple.stackexchange.com/a/323497/18679
    3. Use third party downloader tool (dosdude) -- not tested
      1. See http://dosdude1.com/highsierra/
  2. Get the Install macOS High Sierra.app
    1. Download from the App store (recommended)
    2. Copy from first computer
  3. Copy all installer files (±5 GB) from first computer to /Applications/Install macOS High Sierra/Contents/SharedSupport
    1. Make subdirectory as root SharedSupport first if it doesn't exist (likely) sudo mkdir /Applications/Install\ macOS\ High\ Sierra.app/Contents/SharedSupport/
    2. Copy files to newly created subdir
      1. sudo cp -p /macOS\ Install\ Data/* /Applications/Install\ macOS\ High\ Sierra.app/Contents/SharedSupport/
    3. See macOS High Sierra media installer
  4. Run Install\ macOS\ High\ Sierra.app as usual
  5. Installer should skip downloading and immediately ask to restart

This does not work (for me)

  1. Copy files (as downloaded above) directly to /macOS\ Install\ Data -- the installer program will delete these files and download them again


macOS High Sierra media installer

  • Swap step 2) and step 1) above. i.e get installer first, then download the full image next. – user292048 Jun 15 '18 at 0:22

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