Create a disk image DMG file buy issuing the following command:.

When the “Install MacOS Mojave.app” or “Install MacOS Catalina.app” application is fully downloaded and within the /Applications folder, proceed.

First, download MacOS Mojave installer, or the MacOS Catalina installer (or the installer you wish to turn into an ISO) from the Mac App Store.

This process will take an installer for macOS and create an ISO file from it which can be booted or used as a typical disk image file. How to Create a MacOS Mojave ISO or Catalina ISO File from an Installer You can use the same steps to create an ISO file from practically any other MacOS Installer with createinstallmedia present however, including building a MacOS Catalina ISO, or for Big Sur, High Sierra, and Sierra, simply by replacing the file names where appropriate.

In this particular walkthrough, we’ll be converting a MacOS Mojave installer application into an ISO file. This tutorial will walk through the steps to create an ISO file of a MacOS installer.

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