Apple delivers the macOS installer and applications through the app store since the launch of OS X Lion. The macOS installer has a .app extension when you get it through the official channel. Unlike the macOS DMG installer, which Apple doesn’t provide nowadays, the app version of the macOS install package is not bootable. Hence it is not mountable nor compatible with operating systems like Windows. For some reason, if you want macOS in .DMG or .ISO format, there is a method to convert the .app file. Unfortunately you need a macOS system to convert .app to .dmg to .iso image.
Reasons for converting macOS Mojave or High Sierra .app to .DMG or .ISO
- The macOS in DMG format let to quickly create Install DVDs and bootable USB installers in a few minutes.
- When you convert macOS Install .app to ISO format, you may use it for running macOS on Windows PCs (Hackintosh).
- You can use the DMG file made from the macOS Install app for creating a boot-friendly macOS USB on Windows PC.
Above all, DMG and ISO files are highly portable; it is easy for anyone to upload and transfer them through the Internet.
Convert macOS Installer .APP to .DMG bootable image
The requirement for running macOS, and a USB Pen Drive for converting the Installer application to bootable ISO or DMG image. The step by step process for converting macOS Catalina, Mojave, High Sierra & EI Capitan to the bootable .DMG or .ISO is explained below.
- First of all, download the full MacOS installer, and save it in the Applications folder.
- Next step is to create a bootable macOS USB from the Installer app. I prefer using the macOS Terminal app to create the bootable USB Installer using commands in the screenshots.
- Now, copy the contents of the macOS USB to a new folder and give it a single word name. We are going to make DMG file on Mac from the newly created folder.
- Then open the Disk Utility app and then take the “File” menu from the top left corner. Then New Image and Image from folder, and direct the Finder to the macOS file folder.
- Choose the image format as Hybrid (HFS+/ISO/UDF).
- The system now starts converting the macOS installer .app bootable .DMG file.
Just in case you find any difficulty, check our video on converting macOS installer .app to bootable .dmg.
How to convert macOS installer to iso format
There are several ways to convert macOS .app to .ISO bootable image. Usually one need to do APP to DMG or CDR conversion before making it an ISO file on Mac. The Disk Utility app in macOS previously had an option that allows you to convert DMG to ISO/CDR. You can use Terminal and third-party apps to convert Mac OS installer to ISO if it is in CDR format.
AnyToISO app capable of converting macOS DMG to iso format. The free version of AnyToISO doesn’t support converting dmg files above 850 MB. Hence, you need to either purchase or download (Search AnyToISO Pro 3.9.0 in Google) the PRO version of this app.
In my experience, converting DMG to ISO with AnytoISO takes a lot of space and resources if you’re on macOS machine. The system shows out of space notification even though you have enough space left in the disk. Therefore, it is better to transfer the DMG files to a Windows machine and use freeware like DMGtoISO or AnyBurn for converting. Check our page on burning DMG on Windows for freeware tools supporting DMG to ISO conversion.