deploying Big Sur

Contributor II

I want to use this for upgrading some clients to Big Sur.

While it is downloading the Big Sur PKG it is shown, but then suddenly it dissappears.
Is there something wrong with my pkg?


Contributor III

Try downloading the macOS installer pre-packaged by Apple here...

New Contributor

Hey @DennisMX,

The documentation for whatever reason is wrong, you can't .pkg Big Sur with composer it corrupts the .pkg. If you check the size of the .pkg you made coming out of composer the size is probably 16MB. Instead, make it a .dmg. There are a few approaches you can use to obtain a copy of the Big Sur installer. Personally, I've taken the .dmg approach following the documentation above.

I don't know if there is a benefit of a .pkg over a .dmg, if someone knows let me know please :).

Here is a helpful article from Jamf with a method to download the Big Sur installer versions, it's about halfway down under "Download an installer package from Apple". Reinstall a clean macos with one button. The title says a clean version, but there are instructions on how to not do that, basically just removing the --eraseinstall flag

Valued Contributor


  1. Use to download a full installer.
  2. Use MegaPGKGr.zsh to create your "Install macOS Big Sur".pkg file.
  3. Upload and deploy to your fleet.
  4. Run the startosinstall command to upgrade your fleet.
  5. Profit???

optional: you can also just follow this HCS guide here. I don't know who makes these but they're great. It shows you how to use MegaPKGr.zsh on page 12 FYI.

New Contributor III

Bro, i am getting the following error i was trying to download the macOS Big Sur.

Making empty sparseimage...

installer: Package name is macOS Big Sur

installer: Installing at base path /private/tmp/dmg.9lL2zl

installer: The install failed. (The Installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance. An error occurred while running scripts from the package “InstallAssistant.pkg”.)

Command '[u'/usr/sbin/installer', u'-pkg', u'./content/downloads/43/16/071-78704-A_U5B3K7DQY9/cj9xbdobsdoe67yq9e1w2x0cafwjk8ofkr/071-78704.English.dist', u'-target', '/private/tmp/dmg.9lL2zl']' returned non-zero exit status 1

Product installation failed.


Valued Contributor

Use the clear cache flag next time when running

New Contributor III

Tried the clear cache flag but still gets the same error. --ignore-cache 

Contributor II

thanks all for thinking with tme here.
I manage to make it work, maybe not beautiful. But it works.

I downloaded the PKG from MrMacintosh.
Made it available as a cached package (Scope: smart group with old OS macbooks i want to upgrade)
Created a 2nd policy to install the cached PKG (Scope: a smart group that checks if the package is cache (previous policy)
Then policy 3 uses this script to upgrade the OS (Scope: check if Install macOS Big is available)

Wouldn't it be nice if Jamf partnered up with Apple to just make instant workflow/policy available to upgrade to a OS version you can select from a dropdown menu?

Jamf Pro was able to accept the 12GB pkg?

I am uploading it now, but I remember I had an issue with Catalina where it said pending availability and that never went away (it actually still says it today after over a year).