We are upgrading macOS (minor versions and potentially major versions) using a scripted approach:
Install the InstallAssistant package via installer Trigger OS install via startosinstall On MDM-managed assets, OS update policies appear to prohibit or interfere with the update flow. The update often fails with startosinstall reporting “Helper tool crashed…” during the “Preparing” phase.
Steps to Reproduce
On an MDM-enrolled Mac with OS update restriction/deferral policies applied, run:
sudo /usr/sbin/installer -pkg /Path/To/InstallAssistant.pkg -target / &&
echo 'MACOS_PASSWORD' | /Applications/Install\ macOS\ Sonoma.app/Contents/Resources/startosinstall
--agreetolicense
--forcequitapps
--stdinpass
--user MACOS_USER
Actual Result Package installation reports success, but startosinstall fails during preparation with:
Standard Output
installer: Package name is macOS15.7_SoftwareUpdate installer: Upgrading at base path / installer: The upgrade was successful. By using the agreetolicense option, you are agreeing that you have run this tool with the license only option and have read and agreed to the terms. If you do not agree, press CTRL-C and cancel this process immediately. Preparing to run macOS Installer...
Preparing: 0.0% Preparing: 0.1% ... Preparing: 24.9%
Standard Error
Helper tool crashed...
Install.log is also attached.Questions for Apple / Ask:
We suspect this crash is caused by MDM OS update restrictions/policies.
We need Apple’s recommended method to perform macOS updates (minor + major) when MDM is present, especially in environments where update deferrals/restrictions may be configured.