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A bare-bones tool to install macOS and a set of packages on a target volume. Typically these are packages that "enroll" the machine into your management system. Upon completion of the macOS install, these tools take over and continue the setup and configuration of the machine.

installr is designed to run in Recovery boot (and also possibly Internet Recovery), allowing you to reinstall a machine for redeployment.

If you are preparing a fresh-out-of-the-box machine, consider NOT reinstalling macOS and just installing your additional packages. bootstrappr can help you with that task.

macOS Installer

Copy an Install macOS application into the install/ directory. This must be a "full" installer, containing the Contents/Resources/startosinstall tool.

I've tested the following installers:

  • 10.13.4 (17E199)
  • 10.13.6 (17G65)
  • 10.14 (18A391)
  • 10.14.1 (18B75)

Older installers may or may not work.


Add desired packages to the install/packages directory. Ensure all packages you add can be properly installed to volumes other than the current boot volume.

Important: startosinstall requires that all additional packages be Distribution-style packages (typically built with productbuild) and not component-style packages (typically built with pkgbuild). This means that packages you use successfully with bootstrappr (or Imagr or Munki) won't necessarily work with installr; those other tools can install component-style packages. startosinstall will fail with an error if given component-style packages to install.

If your packages just have payloads, they should work fine. You should check that pre- and post-install scripts do not use absolute paths to the current startup volume. The installer system passes the target volume in the third argument ($3) to installation scripts.

startosinstall in High Sierra ignores additional package's RestartActions. This means that if software installed by one or more or your packages requires a restart for full functionality, it won't be fully functional when the High Sierra installer completes its work.


The startosinstall tool will work through the packages in alphanumerical order. To control the order, you can prefix filenames with numbers.

T2 Macs

installr is particularly useful with Macs with T2 chips, which do not support NetBoot, and are tricky to get to boot from external media. To use installr to install macOS and additional packages on a T2 Mac, you'd boot into Recovery (Command-R at startup), mount the installr disk, and run installr.

Usage scenarios

Scenario #1: USB thumbdrive

  • Preparation:
    • Copy the contents of the install/ directory to a USB thumbdrive.
  • Running installr:
    • Start up in Recovery mode.
    • Connect USB thumbdrive.
    • Open Terminal (from the Utilities menu if in Recovery).
    • /Volumes/VOLUME_NAME/run (use sudo if not in Recovery).

Scenario #2: Disk image via HTTP

  • Preparation:
    • Create a disk image using the script.
    • Copy the disk image to a web server.
  • Running installr:
    • Start up in Recovery mode.
    • Open Terminal (from the Utilities menu if in Recovery).
    • hdiutil mount <your_bootstrap_dmg_url>.
    • /Volumes/install/run (use sudo if not in Recovery).


A tool designed for use in Recovery boot to do a "fresh" install of macOS and additional packages.







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