How to Create macOS Golden Gate ISO File: Complete Step-by-Step Guide

A macOS Golden Gate ISO file is the perfect solution for running Apple’s latest operating system in a virtual machine (VMware, Parallels, VirtualBox, UTM), creating a bootable installer, or performing clean installations across multiple Macs without downloading the installer each time.

Unlike Windows, Apple does not provide ISO files directly — but you can easily create one yourself using the official macOS installer and built-in Mac tools. This guide walks you through the process in 8 simple steps, using only Terminal commands.

📁 What Is a macOS Golden Gate ISO and Why Would You Need One?

An ISO file is a disk image that acts as a complete clone of an installer disc. Having a macOS Golden Gate ISO allows you to:

Run macOS in virtual machines – Test the new OS in VMware, Parallels, VirtualBox, or UTM without affecting your main system.
Perform clean installations – Wipe your drive and install a fresh copy of macOS Golden Gate on any compatible Mac.
Create bootable USB drives – Use the ISO to make a physical installation disk for recovery or multiple installs. You can read this guide: How to Create a macOS Golden Gate Bootable USB for Clean Installation
Set up isolated testing environments – Test beta apps or new workflows without risking your primary setup.
Keep an offline backup – Never wait for a re-download again; simply fire up your saved ISO whenever needed.

Good to know: The process shown here works for all modern macOS versions from Big Sur onward, including macOS Golden Gate. The only requirement is that you use a Mac — these steps cannot be performed on Windows.

You can also download the macOS Golden Gate ISO directly here.

🛠️ Prerequisites

Before you begin, make sure you have:

Requirement	Details
A compatible Mac	Any Intel or Apple Silicon Mac running macOS Big Sur or newer.
Free storage space	At least 25–30 GB of free space on your startup drive.
Internet connection	Required to download the InstallAssistant.pkg file.
macOS Golden Gate installer	The full “Install macOS Golden Gate.app” in your Applications folder.
Terminal	Found in Applications → Utilities.

📥 Step 1: Download the macOS Golden Gate Installer

To create an ISO, you first need the official macOS installer in .app format.

Visit our guide: Download macOS Golden Gate Full Installer (.PKG) file: How to install?
Download the InstallAssistant.pkg file.
Double-click the downloaded InstallAssistant.pkg file to launch it.
Follow the on‑screen instructions to install it.

Once complete, you will find “Install macOS Golden Gate.app” inside your Applications folder. This is the full installer we will use to create the ISO.

How to Create macOS Golden Gate ISO File: Complete Step-by-Step Guide

Note: If you are using a beta build, the app may be named Install macOS 27 Beta.app. Adjust the commands accordingly.

🧱 Step 2: Prepare the Installer (Run Once)

Before building the ISO, run the installer app once to ensure macOS fully recognizes it.

Open Finder → Applications.
Locate Install macOS Golden Gate.app.
Double-click it. The installer window will open — you can close it immediately. This step simply verifies the installer is intact and ready for use by Terminal commands.

💿 Step 3: Create a Blank Disk Image

We need an empty container (a disk image) for building the bootable installer.

Open Terminal (Applications → Utilities) and run the following command:

hdiutil create -o ~/Desktop/Golden -size 20000m -volname Golden -layout SPUD -fs HFS+J

What this command does:

Creates a 20 GB (20000 MB) blank disk image named Golden.dmg on your Desktop.
Formats it as Mac OS Extended (Journaled) (HFS+J).
Uses a single‑partition layout (SPUD) to avoid compatibility issues.

Why 20 GB? The macOS Golden Gate installer requires roughly 15–18 GB of space. A 20 GB image provides a comfortable safety margin. If you receive an “out of space” error later, increase the size to 25000m or 30000m and restart from this step.

🔗 Step 4: Mount the Disk Image

Now mount the blank disk image so macOS can see it as a usable volume.

In the same Terminal window, run:

hdiutil attach ~/Desktop/Golden.dmg -noverify -mountpoint /Volumes/Golden

What this does:

Attaches the Golden.dmg file to your system.
Makes it available at the mount point /Volumes/Golden.
You should now see a volume named “Golden” appear in your Finder sidebar and on your Desktop.

Troubleshooting: If you see a “Resource busy” error, make sure no other process is accessing /Volumes/Golden. Try unmounting any existing volume with that name first using hdiutil detach /Volumes/Golden.

⚙️ Step 5: Build the Bootable Installer Using createinstallmedia

This is the most critical step. We will use Apple’s built‑in createinstallmedia tool to copy the macOS installer onto our mounted disk image and make it bootable.

Run this command (you will be prompted for your administrator password):

sudo /Applications/Install\ macOS\ Golden\ Gate.app/Contents/Resources/createinstallmedia --volume /Volumes/Golden --nointeraction

If you are using a beta version, adjust the path accordingly:

sudo /Applications/Install\ macOS\ 27\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Golden

What happens next:

The system will ask for your password (it will not appear on screen — type it and press Enter).
The tool erases the mounted volume and copies all installer files onto it.
The process takes approximately 10–20 minutes, depending on your Mac’s speed and storage.
You will see progress messages in Terminal, culminating in:

Install media now available at “/Volumes/Golden”

The --nointeraction flag: This automatically confirms “Y” when asked, making the process fully scriptable. If you prefer to approve manually, simply omit this flag.

🔌 Step 6: Unmount the Volume

Once the createinstallmedia command completes successfully, you must unmount the volume before converting it to an ISO.

Run the following command:

sudo hdiutil detach /Volumes/Install\ macOS\ Golden\ Gate

If using Beta version:

sudo hdiutil detach /Volumes/Install\ macOS\ 27\ beta

Note: The exact volume name after detach may be Install macOS Golden Gate rather than just Golden. To confirm the mounted volume name, look in your Finder sidebar or run ls /Volumes/ in Terminal. Adjust the command accordingly.

If you are unsure of the exact name, you can also detach the volume by unmounting it in Finder: right-click the volume on your Desktop and select Eject.

🔄 Step 7: Convert the DMG to ISO Format

Now we convert the disk image (.dmg) into a universally recognized ISO file.

Run these two commands in sequence:

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

mv ~/Desktop/Golden.cdr ~/Desktop/Golden.iso

What these commands do:

The first command converts the DMG to Apple’s UDTO format (which is essentially a CD/DVD master file, saved with a .cdr extension).
The second command renames the .cdr file to .iso, making it compatible with virtualization software and other platforms.

Once finished, you will find Golden.iso on your Desktop. The original Golden.dmg and the temporary .cdr file can be deleted to free up space.

Why this two‑step process? Apple’s hdiutil convert can output directly to ISO-compatible formats, but the UDTO method produces the most reliable bootable ISO for virtual machines. The .cdr extension is functionally identical to .iso — only the file suffix differs.

✅ Step 8: Verify the ISO File

Before using your newly created ISO, it is wise to verify that it works correctly.

Check the file size – The ISO should be roughly 15–18 GB. Right-click the file and select Get Info to confirm.
Test it in a virtual machine – Create a new VM in VirtualBox, VMware Fusion, or UTM, attach the ISO as a virtual DVD, and boot from it. If the macOS installer appears, your ISO is working perfectly.
Check the volume contents – Double-click the ISO file to mount it. You should see the standard macOS installer files (e.g., Install macOS Golden Gate.app, a System folder, and other boot files).

🖥️ Using Your macOS Golden Gate ISO in Virtual Machines

Now that you have a functional ISO, here is how to use it in the most popular virtualization platforms:

VMware Fusion / Workstation

Create a new virtual machine.
Select “Install from disc or image” and choose your Golden.iso.
Follow the on‑screen instructions — the macOS installer will boot from the ISO.
Complete the installation as you would on a physical Mac.

Parallels Desktop

Open Parallels Desktop → File → New.
Choose “Install from an image file” and locate your ISO.
Parallels will detect macOS Golden Gate automatically and guide you through the setup.

Oracle VirtualBox

VirtualBox requires a bit more configuration for macOS guests. After creating a new VM:

In the VM settings → Storage, add the ISO to the optical drive.
Enable EFI (System → Enable EFI).
For Apple Silicon Macs, note that VirtualBox on ARM is still evolving; consider using UTM instead for better compatibility.
Boot the VM and proceed with the installation.

UTM (best for Apple Silicon Macs)

Create a new virtual machine → Emulate (for Intel macOS) or Virtualize (for ARM builds).
For the boot disk image, select your Golden.iso.
Start the VM — the installer should boot without issues.

Important: macOS Golden Gate runs exclusively on Apple Silicon Macs. If you are creating a VM on an Intel host, you are emulating an ARM environment, which will be extremely slow. VMs of macOS Golden Gate work best when run on Apple Silicon hardware with proper virtualization support.

📊 Terminal Command Summary (Quick Copy-Paste)

For your convenience, here are all the commands in sequence. Copy and paste them one by one, adjusting the installer path and volume name as needed.

hdiutil create -o ~/Desktop/Golden -size 20000m -volname Golden -layout SPUD -fs HFS+J

hdiutil attach ~/Desktop/Golden.dmg -noverify -mountpoint /Volumes/Golden

sudo /Applications/Install\ macOS\ Golden\ Gate.app/Contents/Resources/createinstallmedia --volume /Volumes/Golden --nointeraction

If you are using a beta version, adjust the path accordingly:

sudo /Applications/Install\ macOS\ 27\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Golden

sudo hdiutil detach /Volumes/Install\ macOS\ Golden\ Gate

If you are using a beta version, adjust the path accordingly:

sudo hdiutil detach /Volumes/Install\ macOS\ 27\ beta

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

mv ~/Desktop/Golden.cdr ~/Desktop/Golden.iso

⚠️ Troubleshooting Common Issues

Problem	Solution
“Not enough space” error in Step 3 or 5	Increase the `-size` parameter to `30000m` (30 GB). Delete the existing `Golden.dmg` first: `rm ~/Desktop/Golden.dmg`. Then rerun Step 3.
“createinstallmedia: command not found”	Verify the installer path is correct. Navigate to `/Applications/Install macOS Golden Gate.app/Contents/Resources/` in Finder to confirm the `createinstallmedia` file exists.
“Could not mount disk image”	Ensure no other process is using the mount point. Run `hdiutil detach /Volumes/Golden` to clear any existing attachment, then retry Step 4.
ISO won’t boot in a virtual machine	Make sure your VM is set to boot from a DVD/optical drive (not a hard disk). Some virtualization software requires the ISO to be inserted after the VM is created but before it is powered on.
The installer says “This copy is damaged”	Your Mac’s date may be incorrect for the installer’s certificate. Open Terminal from the Utilities menu (inside the installer) and run: `date 0101010116`. Then retry the installation.
VM hangs on a black screen after boot	In VirtualBox, ensure EFI is enabled and allocate at least 8 GB of RAM to the VM. For UTM, try switching the display driver to “virtio‑ramfb” or “vmware‑svga”.

🧹 Cleaning Up

After successfully creating your ISO, you can reclaim disk space by deleting temporary files:

rm ~/Desktop/Golden.dmg
rm /tmp/Golden.sparseimage   # if this file exists

The final ISO remains on your Desktop, ready for use.

❓ Frequently Asked Questions

Q: Can I create a macOS Golden Gate ISO on a Windows PC?
A: Not directly. The createinstallmedia tool is a macOS‑only utility. However, you can use pre‑built ISO files from trusted sources or run a macOS virtual machine on Windows to perform this process.

Q: Will the ISO work on Intel Macs?
A: The ISO will boot, but macOS Golden Gate cannot be installed on Intel Macs. The operating system runs exclusively on Apple Silicon (M1/M2/M3/M4). You can still use the ISO in a virtual machine on Intel hardware for emulation (though performance will be poor).

Q: How much time does the whole process take?
A: Approximately 30–45 minutes, depending on your Mac’s speed and storage. Step 5 (createinstallmedia) is the longest, taking 10–20 minutes on its own.

Q: Can I use this ISO to create a bootable USB drive?
A: Yes. You can restore the ISO to a USB drive using dd in Terminal or tools like BalenaEtcher. However, for a physical USB installer, it is simpler to use the original InstallAssistant.pkg method described in our other guides.

Q: Does the ISO include recovery tools?
A: Yes. The ISO created with createinstallmedia contains the full macOS recovery environment, including Disk Utility, Terminal, and the macOS installer itself.

🎯 Final Thoughts

Creating a macOS Golden Gate ISO is a straightforward process once you know the Terminal commands. Whether you are a developer setting up isolated testing environments, an IT administrator deploying macOS across multiple machines, or simply someone who wants an offline backup installer, this guide has everything you need.

Recap of the 8 steps:

Download and install the macOS Golden Gate installer.
Run the installer once to verify it.
Create a blank disk image (DMG) with hdiutil.
Mount the disk image.
Use createinstallmedia to build a bootable installer on the mounted volume.
Unmount the volume.
Convert the DMG to ISO format.
Verify the ISO works in a virtual machine.

With your new Golden.iso ready on your Desktop, you can now run macOS Golden Gate anywhere virtualization is supported — all without needing to download the installer more than once.