I have downloaded /Applications/Install macOS High Sierra.app I'd like to burn an .iso file I can install in VirtualBox on a newer mac that runs Catalina.


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    Oct 24, 2023 at 20:42

2 Answers 2


You do not use an .iso to install High Sierra. You use a .vdi instead.

I have had problems using any of the version 7 Virtual Box releases when the host is Catalina. This answer was tested using VirtualBox version 6.1.44 on 2013 iMac with macOS Catalina version 10.15.7 installed.

The steps to create the .vdi are given below. Here I assume your Install macOS High Sierra application is complete. In other words, the size of the application should be about 5.24 GB.

  1. Set the variable SIZE to be the size of the disk images to be created, which will contain the High Sierra installer files. Here a value of 16 GiB was chosen. Since both disk images will be dynamically allocated, the actual physical space occupied by each disk image file will be about 5 to 6 GB.

  2. Create a new dynamically allocated disk image containing a JHFS+ formatted volume named MyVolume. The image will be stored in the file named HighSierraInstaller.sparseimage.

    hdiutil create -size $SIZE -fs jhfs+ -volname MyVolume -type SPARSE -attach HighSierraInstaller
  3. Set the variable ID to the identifier assign to the attached image. This identifier can be set manually after observing the output from the previous step or can be set by entering the commands given below.

    ID="$(diskutil info MyVolume | grep -i "Part of Whole")"
    ID="${ID##* }"
  4. Write the High Sierra installer files to the volume named MyVolume. The volume name will change to Install macOS High Sierra.

    sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
  5. (This step is optional.) VirtualBox has been known to boot to an UEFI shell instead of from the Install macOS High Sierra volume. Adding the following startup.nsh file will cause an UEFI shell to automatically execute the macOS High Sierra installer boot file.

    echo -E '\System\Library\CoreServices\boot.efi' >'/Volumes/Install macOS High Sierra/startup.nsh'
  6. Unmount the volume named Install macOS High Sierra.

    diskutil unmountdisk $ID
  7. Create the dynamically allocated disk image file HighSierraInstaller.vdi. This file is compatible with VirtualBox.

    dd if=/dev/r$ID bs=1m | VBoxManage convertfromraw stdin HighSierraInstaller.vdi $SIZE

    The “Oracle® VirtualBox® User Manual Version 7.0.12” states the following:

    Note: For compatibility with earlier versions of Oracle VM VirtualBox, you can use the VBoxManage convertdd command instead of the VBoxManage convertfromraw command.

  8. Eject the disk image containing the volume named Install macOS High Sierra.

    hdiutil detach $ID
  9. Remove the original disk image file HighSierraInstaller.sparseimage.

    rm HighSierraInstaller.sparseimage

When finished, edit the VirtualBox settings for the High Sierra virtual machine. Add HighSierraInstaller.vdi as a second hard disk. The image below shows the second disk added to the virtual machine named "High Sierra".

I would also recommend setting the number processors to at least 2 CPUs, as shown below.

Next, start the virtual machine and install High Sierra. Do not forget to use the Disk Utility to initialize the first drive. If you encounter a display similar to the image shown below, then select the Cancel button to proceed with the installation.

After you are finished installing High Sierra, you can edit the settings and remove the second drive.


Normally Apple will not let you run older than macOS shipped with a Mac.

Command softwareupdate in Terminal tells you what macOS version(s) can be downloaded and installed on your Mac:

softwareupdate --list-full-installers

Source: How to Download Full MacOS Installers from Command Line

  • The command softwareupdate --list-full-installers does not work with Catalina. Oct 25, 2023 at 8:35
  • Often you can run versions of OS X/macOS in a virtual machine as a guest even when the same version will not run on the host Mac. Apple allows Mountain Lion (10.8) through Catalina (10.15) to run on my 2013 iMac. However, I can run Snow Leopard (10.6) through Monterey (12) in various virtual machines as guests. Oct 25, 2023 at 8:43
  • OP isn't asking how to download, but [correctly or incorrectly] how to burn to DVD. This doesn't attempt to answer that question, nor even challenge its assumption.
    – Tetsujin
    Oct 25, 2023 at 10:56

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