Trying to create a old OS X virtual machine, but can't get it run the installer.

[ronmacstein]

I am running Fusion 11 on an iMac running Catalina.

I want to create a virtual machine that is running an older version of the Mac OS (El Capitan).

I have an old piece of software that won't run after El Capitan.

I obtained a disk image for the installation of El Capitan from the Apple Support site (InstallMacOSX.dmg).

I created a new virtual machine and pointed it to the disk image via The Startup Disk and CD/DVD in the Virtual Machine Setting menu.

I keep getting this error message.

Can anyone help me on this?

Thanks.

[dempson · Accepted solution]

This problem has come up before and I gave a more detailed answer at the time. Here is a somewhat abridged version.

The key detail is that you can't use that InstallMacOSX.dmg file to create a VM. You need to open the .dmg in macOS and run the installer package inside it, which will create an "Install OS X El Capitan" application in your Applications folder. That application is the file you need to create an El Capitan VM.

The catch is that you can only do this on a Mac which is able to boot El Capitan. If your iMac is a 2017 or later model, then it is too new to run El Capitan, so the installer package inside the disk image will refuse to proceed.

If you don't have access to a suitable older Mac model, the workaround is to create a temporary VM for a later macOS which your Mac is able to run, e.g. Mojave would cover 2017 and 2019 iMacs. You can download the Mojave installer from Apple's support page (it comes as an application, not a disk image, so it can be used directly to create the Mojave VM). Once you have the Mojave VM, you can open the El Captain "InstallMacOSX.dmg" file from inside that VM and run the installer, which creates the "Install OS X El Capitan" application, copy that application out to the host then use it to create your El Capitan VM (and delete the temp Mojave VM if you don't need it for anything else).

The reason this works is that the installer package on the disk image and the actual macOS installer bypass the model check if they detect they are running inside a VM.

Make sure you allow enough disk space inside the temp VM: apart from the requirements of the OS it is running, the "Install OS X El Capitan" application is about 6.3 GB (plus the size of the disk image if you copy it into the VM).

[ColoradoMarmot]

Just drag the DMG to the new VM window - no need to mount or set as the startup volume.

[ronmacstein]

Thanks for your help.

I really appreciate the time you took to respond.

I am getting much farther, but not to the goal yet.

Here's what I did.

I copied the Install El Capitan app (6.2 Gig) from the Applications folder on my old Mac Pro (which is running El Capitan).

I pointed the new VM to that file.

It creates the new VM and starts the install then it just stops after a couple of minutes with the below screen.

[dempson]

Just drag the DMG to the new VM window - no need to mount or set as the startup volume.

That won't work. The .dmg which Apple supplies is not bootable. It only contains an installer package (which when installed creates "Install OS X El Capitan.app").

[dempson]

I copied the Install El Capitan app (6.2 Gig) from the Applications folder on my old Mac Pro (which is running El Capitan).

Was that a a copy of the Install El Capitan app you downloaded a while ago?

If so, you've run into a second issue - installers downloaded prior to October 2019 don't work any more due to a certificate expiring. You need a newer copy of the installer, which you can create using the "InstallMacOSX.dmg" you already downloaded on your iMac.

1. On the Mac Pro, delete your old "Install OS X El Capitan.app".

2. Copy "InstallMacOSX.dmg" from the iMac to the Mac Pro.

3. On the Mac Pro, open "InstallMacOSX.dmg", open the installer package inside it and run through that. This gives you a fresh "Install OS X El Capitan.app" with an updated certificate.

4. Copy the new "Install OS X El Capitan.app" to your iMac and use it to create your VM.

[ColoradoMarmot]

You're right - Apple doesn't provide a DMG - they only provide a downloadable .app installer.  That's what you drag to the new VM wizard window.

[ronmacstein]

I did as you outlined and ALL IS WELL!

I have my old software and hardware running on my new Mac in a virtual machine.

Thanks again for your help, I would have never gotten here without it.

Ron

[dempson]

dlhotka Apple does indeed provide a DMG for older versions of OS X. At present you can only directly get a .app installer for High Sierra, Mojave and Catalina. The support articles to get Yosemite, El Capitan or Sierra link to a .dmg file, which contains a .pkg installer, which installs the .app, and the latter is the one you need to create the VM.

[wila]

Dlhotka, just to confirm what dempson says.

It works like you say for newer versions of macOS (High Sierra and later), the older OS X versions can't be dropped on the new VM panel.

As such Fusion is not creating a helper virtual disk with the installer to run from.

I was under the same impression than you are and downloaded new installers for the old OS X versions.

For those versions of OSX/macOS you'll end up with dmg files. The .dmg's have InstallMacOS.pkg or InstallOSX.pkg in them.

After that then I tried to drop them on the New VM pane in VMware Fusion 11.5.5

Couldn't drop them there.

--

Wil

[dariusd]

Thanks for reporting this, everyone.  It took me a while to follow what was happening – and to realize that it really wasn't user error or one of the many other ways that macOS installations can go amiss... sorry!

I can reproduce the problem with the image downloaded from the Apple Support article on upgrading to OS X Yosemite.  I would like to think that we have an opportunity to improve the user experience here, although it might be technically challenging to achieve an improvement without requiring another 6-7 GBytes of storage space to set up the OS X Yosemite temporary installation source medium.  Sigh.

Anyway, I'll put it on my to-do list to investigate.

Thanks again,

--

Darius

[ColoradoMarmot]

Ahh, ok.  I have the old .app's still hanging around.