How to Create a macOS Big Sur ISO File Using Terminal

There are multiple reasons why you might want to create a macOS Big Sur ISO file. Maybe you want to install macOS on virtual machines like VMWare and Parallels Desktop for extensive testing. Perhaps you are ready to create an alternative installation media on an external hard drive. Whatever your reason for creating a macOS Big Sur ISO file, you’ll be pleased to know that it’s possible to fine-tune a fully functional ISO file without having to use any third-party tools. If you’re ready, let me guide you!

Create a macOS Big Sur ISO File Using the Terminal App

So how do you get an ISO file on Mac? With the built-in application called Terminal, you can create an operable ISO file via the command line. For those wondering why the whole process needs Terminal or a third-party app, it’s because the macOS installer app is actually an .app file (not a disk image).

It is worth noting that you can use the same process to create an ISO file for previous generation macOS like macOS Catalina and Mojave. So even if you want the file for older macOS generations, the following steps may help you. Having said that, let’s go!

  1. To get started, go to: Mac App Store and download Installer app for macOS Big Sur. Once the macOS installer app (called macOS Big is downloaded, Applications file.

2. Open it now terminal application. You can start at. Applications > Utilities file. Alternatively, you can press the key. Command+Space and call Terminal application to find it quickly.

Launch Terminal app on Mac

3. It’s your turn create a temporary disk image. Start terminal and run the following command.

hdiutil create -o /tmp/MacBigSur -size 12500m -volname MacBigSur -layout SPUD -fs HFS+J

Create a temporary disk image

4. Next, what you need to do mount disk image:

hdiutil attach /tmp/MacBigSur.dmg -noverify -mountpoint /Volumes/MacBigSur

Now mount the disk image

5th place, copy the installer files To the disk image we just created using the createinstallmedia utility, which is part of the macOS Installer application.

sudo /Applications/Install\ macOS\ Big\ Sur/Contents/Resources/createinstallmedia --volume /Volumes/MacBigSur --nointeraction

Now copy the installer file

6. Now, press return and then type admin password to verify. Now you have to wait for a while until the installer is created. After the process is complete what you need to do disconnect the disk image Sound.

hdiutil detach /Volumes/MacBigSur/

Time to unmount disk image

7. Next, convert newly created macOS Insaller disk image file to an ISO/CDR file. Now, it will appear on the desktop.

hdiutil convert /tmp/MacBigSur.dmg -format UDTO -o ~/Desktop/MacBigSur.cdr

Make sure to convert the newly created macOS Insaller disc image file to an ISO:CDR file.

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8. Next, change file extension from .cdr to .iso.

mv ~/Desktop/MacBigSur.cdr ~/Desktop/BigSur.iso

Next, change the file extension from .cdr to .iso.

That is all! You have successfully created a macOS Big Sur ISO file (called BigSur.iso) on your Mac.

How to Create a macOS Big Sur ISO File

Create a macOS Big Sur ISO File with Terminal

So you can create a functional ISO file using the Terminal app on your Mac. It’s good that the first-party app works reliably in creating an ISO file, as you don’t have to look for third-party software or even spend a little money. As someone who relies heavily on the Terminal to do this, I must say that you can more often rely on the app to do the task.

While it is also possible to convert dmg and CDR files to ISO with the help of Disk Utility, the whole process does not come easy. Therefore, I do not recommend it. In the meantime, do you have any questions or feedback? Be sure to write your thoughts on this topic. Also, be sure to read our other articles on macOS Big Sur, including our collection of the best Big Sur widgets, solving battery drain issues in Big Sur, and more.

Moyens Staff
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