At WWDC a few weeks ago, Apple revealed macOS Catalina and made the beta available to developers. If you want to give it a try right now, you should proceed with caution.
And when I say proceed with caution, I really mean DO NOT INSTALL THIS ON YOUR PRIMARY MACHINE!
With all beta software comes a guarantee that it will be buggy, incomplete, unstable, or downright dangerous to rely on. That’s the reality of software development, folks.
True developers can take this risk because they usually have multiple Macs, so putting a beta operating system on one minimizes the risk of them losing everything. Whereas if you only have your one Mac (like most sane people), then you’re asking for trouble.
However, let’s say you’re a small indie developer with only one Mac, or you just really, really want to give constructive feedback on the next release of macOS before it’s public, there’s an option for you.
Running macOS Catalina in a VM allows you to give the OS a try in a siloed environment without compromising your Mac. Because Catalina is a brand new, unreleased operating system, no virtualization software currently supports it.
But all is not lost!
My choice of virtualization software is VMware Fusion. I’m sure you could do this in Parallels, but I don’t have any experience with that.
If you try to upgrade a macOS Mojave VM to Catalina, it will fail to boot during the upgrade. If you try to setup a macOS Catalina VM blindly, it will fail to boot during the setup.
User Intell008 on the VMware Community Forums is to thank for discovering how to get around these issues. I expanded on his instructions a bit and included screenshots.
I’m assuming you already have the Install macOS Catalina Beta.app installer already. This setup used the Developer Preview 2 (build 19A487l) released June 17th, 2019.
Step 1 – Create new Virtual Machine
Drag the Install macOS Catalina Beta.app to the Install from Disc or Image space on the new VM window. Do not use the InstallESD.dmg file if you went looking for that. Click Continue on the next window.
Step 2 – Choose Operating System
Here’s where you have to deviate from the obvious. Normally, VMware can detect the OS from the installer and you’re not presented with this window, but VMware doesn’t yet know that 10.15 exists. You must select the newest option Vmware Fusion: Apple OS X > macOS 10.14. Click Continue.
Step 3 – Customize Settings
Click Customize Settings at the bottom of the next window. It will ask you where you want to save your VM container, then it will create the installation media – this may take a few minutes.
Now things get really weird.
Before you start your newly-created VM, in its settings, under General, change the OS from macOS 10.14 to Windows 10 x64. Yes, trust me. Click Change in the warning.
Now click Show All, and go to the Keyboard & Mouse pane. Change the Profile to Windows 10 Profile.
Don’t skip Step 2 above. The VM must be created at macOS 10.14 first, then switched to Windows 10 x64.
Step 4 – Start the VM
Now start the VM and go through the installation like you would expect. This will take about 15-20 minutes depending on your host hardware.
Step 5 – Switch Back
Once the installation is complete, your VM is going to try to boot into macOS Catalina. However, it will fail to boot.
Shutdown the VM. Go back to your General settings and revert the OS back to macOS 10.14. Don’t forget your Keyboard & Mouse settings as well, or else you won’t be able to click or type!
Boot up the VM, go through the user setup, then install VMware Tools.
Voila! It’s not perfect, but it’s a usable demo of a beta operating system. I should also note that running macOS in a virtual machine is a violation of the macOS Terms and Conditions, but you didn’t read those anyway so what does it matter?