Download the macOS 27 Golden Gate restore image, point any major virtualization app at it, and the installation fails partway through, every time, with a generic "An error occurred during installation. Installation failed." This is not specific to one app or one Mac. It affects Parallels, UTM, VMware Fusion, Tart, and VirtualBuddy identically, and it comes down to a single, confirmed incompatibility that has nothing to do with your settings.

The error you are seeing

The failure pattern is consistent across every affected tool: the install begins normally, often progresses to somewhere between 70 and 80 percent, then stops with a generic installation-failed error. In UTM specifically, the underlying system error reported is from Apple's own VZMacOSInstaller framework, which every one of these virtualization apps uses under the hood on Apple Silicon. Installing Xcode's command-line components or additional developer tools beforehand does not fix it, despite being a common first guess.

The actual cause

This is a confirmed incompatibility between the VZMacOSInstaller API as implemented in macOS 26.6 (the host system doing the installing) and the installer image for macOS 27. In plain terms: if the Mac you're virtualizing from is running macOS 26.6 Tahoe, Apple's own virtualization framework on that host cannot correctly process the Golden Gate installer image, regardless of which third-party app is calling that framework. Every virtualization app sits on top of the same Apple framework here, which is exactly why the bug shows up identically everywhere.

Fix 1: build the VM on a Mac already running Golden Gate

The most direct fix, confirmed by an Apple engineer on Apple's own developer forums during the beta cycle, is to flip which macOS version is doing the installing:

  1. Find a physical Mac that is already running macOS 27 Golden Gate as its main operating system.
  2. Create the Golden Gate virtual machine on that Mac, using the same virtualization app you were already trying to use. Because the host is now running 27, the VZMacOSInstaller incompatibility doesn't apply, and installation completes normally.
  3. Copy the resulting virtual machine's disk image back to your original Mac, even if that Mac is still on Tahoe. A completed Golden Gate VM runs fine as a guest on an older host; the incompatibility is specifically in the installation step, not in running an already-built VM.

This requires access to a second Mac already on Golden Gate, which not everyone has. If you don't, use one of the fixes below instead.

Fix 2: install Tahoe first, then upgrade inside the VM

If you only have one Mac and it's on Tahoe, you can sidestep the broken installer path entirely by not using the Golden Gate IPSW to install at all:

  1. Create a new virtual machine using the macOS Tahoe restore image instead of the Golden Gate one. Tahoe installs normally in every current virtualization app, since this bug is specific to the Golden Gate installer image.
  2. Once the Tahoe VM is set up and running, open System Settings inside the virtual machine and go to Software Update.
  3. Opt into the Golden Gate beta channel if the public release hasn't rolled out to that VM yet, or simply check for the regular update if it has.
  4. Update the VM from inside itself, the same way you would update a physical Mac. This upgrade path doesn't go through the same installer mechanism that fails, so it completes normally.

This takes longer than a direct install, since you're setting up Tahoe first and then updating, but it reliably produces a working Golden Gate VM using only the one Mac you already have.

Fix 3: use a patched installer tool

Some virtualization tools have shipped their own workaround specifically for this bug, implementing a different installation mechanism that avoids the broken code path entirely. VirtualBuddy, for example, released a beta update specifically described as adding "a new macOS virtual machine installation mechanism that works around the Virtualization bugs that are preventing macOS 27 virtual machines from being installed successfully in macOS 26 hosts." If you're not tied to a specific virtualization app, checking whether your tool of choice has shipped a similar patch is worth doing before falling back to Fix 1 or Fix 2.

Which fix to pick

Your situationBest fix
You have access to a second Mac already on Golden GateFix 1: build there, copy the VM back
You only have one Mac, still on TahoeFix 2: install Tahoe in the VM, then update it
Your virtualization app has shipped a specific patchFix 3: use the patched installer directly

If you're testing Golden Gate specifically to check app compatibility or try new features without touching your main Mac, our guide to testing Golden Gate safely covers the broader setup, including whether a VM or an external drive is the better choice for your situation.

The short version

  • macOS 27 Golden Gate fails to install in every major virtualization app when the host Mac is running macOS 26.6, because of a confirmed incompatibility in Apple's own VZMacOSInstaller framework, not an app-specific bug.
  • Building the VM on a Mac already running Golden Gate, then copying the finished VM back, is the most direct fix.
  • With only one Mac on Tahoe, install a Tahoe VM first and update it to Golden Gate from inside the VM, which avoids the broken installer path entirely.
  • Some virtualization tools, including VirtualBuddy, have shipped their own workaround specifically for this issue.