Create Dmg Image Mac Os X

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  1. Create Dmg Image Mac Os X 10.10
  2. Create Dmg Image Mac Os X Download
  1. To create a bootable USB drive from a DMG file on Windows, you will need to have the right utility. That's because DMG is not native on Windows. It is the Mac equivalent of an ISO file that has been in use since Apple transitioned from the IMG format with Mac OS X. A DMG file, like ISO, can be used to install macOS operating system or Mac apps.
  2. To create an image from a folder, drag the folder onto the Disk Utility-icon, or choose 'New-Disk image' from folder in the File-menu in Disk Utility. A.dmg file can be a very easy way to send files from one Mac to another. Any Mac can mount and access the Disk Image on their computer.

You can create an empty disk image, add data to it, then use it to create disks, CDs, or DVDs. In the Disk Utility app on your Mac, choose File New Image Blank Image. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

So you downloaded an .iso image, and now you want to convert it to .dmg format? How can I convert .dmg to a Windows-compatible .iso on Mac? Don’t bother downloading any third party software, you can easily convert .dmg to .iso or .iso to .dmg format using the Terminal or Disk Utility on Mac OS X.

Create dmg image mac os x 10.10

Method 1: Convert Between .DMG and .ISO Using Terminal

Mac OS X has a command line tool called hdiutil which allows you to create, mount and convert different types of disk image with ease. Here’s how to convert .dmg to .iso format using the Terminal:

  1. Just press Ctrl + Alt + T on your keyboard to open the Terminal.
  2. Enter the following command into the Terminal window, assuming that you’ve put the .dmg file on your desktop.
    hdiutil makehybrid -iso -joliet -o ~/Desktop/filename.iso ~/Desktop/filename.dmg

    When the process finishes, you’ll get an ISO image that is compatible with Windows, Linux, Ubuntu and Mac.

If you need to convert a disk image from .iso to .dmg, just execute the following command in the Terminal window:
hdiutil convert ~/Desktop/filename.iso -format UDRW -o ~/Desktop/filename.dmg

Sit back and wait for the process to complete.

Method 2: Convert Between .DMG and .ISO Using Disk Utility

  1. Just launch Disk Utility (in /Applications/Utilities). In the menu bar at the top of the screen, select Images -> Convert.
  2. Browse to the .DMG or ISO file you would like to convert, select it and click on the Choose button.
  3. In the pop-up window, select Desktop as your destination. In order to convert .dmg to .iso, make sure to choose DVD/CD master as the Image Format. Click on Convert.

    If you want to convert .iso to .dmg, set the Image Format to “compressed” instead. Click on Convert and you’ll have a .dmg file ready to use.

  4. Simply rename the converted .cdr file to .ISO and you’ll get a Mac-compatible .ISO image. However, a renamed file won’t work on Windows or Linux. To make a Windows/Linux/Mac compatible .ISO file, you have to convert the .cdr file to .iso format using this command:
    hdiutil makehybrid -iso -joliet -o ~/Desktop/filename.iso ~/Desktop/filename.cdr

Conclusion

DMG is a disk image format commonly used by Mac OS X, but it’s practically unusable on Windows or Linux platform. After converting .dmg to .iso on your MacOS, you can copy it to any Windows or Linux computer for burning or mounting.

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Scroll down to “Update and Solution” to see how to get this to work.

Apple recently released new installers for Mac OS X/OS X/mac OS to deal with expired certificates:

Three of the six are links to the Mac App Store:

The other three are URLs to download DMGs:

  • macOS Sierra – InstallOS.dmg
  • OS X El Capitan – InstallMacOSX.dmg
  • OS X Yosemite – InstallMacOSX.dmg

Today I tried (and failed) to create a new Virtual Machine in either Parallels or VMware Fusion using one of these DMGs, specifically, the El Capitan one.

I will explain what I did, and where I got stuck, in the hopes that someone else might figure out what I did wrong and point me in the right direction.

Download the DMG

Apple has created three DMGs for Yosemite, El Capitan, and Sierra, but couldn’t be bothered to give them useful names, so Yosemite and El Capitan are called ‘InstallMacOSX.dmg’ and Sierra is ‘InstallOS.dmg’.

Likewise the DMGs aren’t named usefully when you mount them either, so make sure you name the DMGs well when you download them to avoid confusion. Here’s how to download it and rename it at the same time

Mount the DMG

Open the ‘~/Downloads/InstallElCapitan.dmg’

That will leave you with

“/Volumes/Install OS X/InstallMacOSX.pkg”

Extract the App

Don’t try to install from that .pkg file, it probably won’t work unless the Mac you’re using is capable of running El Capitan:

Instead, open it with Suspicious Package which will let you examine the contents of the .pkg file, as shown here:

Note the area in the red box. Obviously that’s not the full installer, despite the .dmg being over 6 GB. But let’s export it anyway:

Save it to /Applications/ (or wherever you prefer, but that’s where I’ll assume it is for the rest of these instructions).

Don’t eject “/Volumes/Install OS X/InstallMacOSX.pkg” yet, we still need to get the actual .dmg from it.

Get the other DMG

Download The Archive Browser if you don’t already have it (it’s free!) and use it to open “/Volumes/Install OS X/InstallMacOSX.pkg”.

Create dmg image mac os x download

It will look like this:

Click on the triangle to the left of “InstallMaxOSX.pkg” to reveal its contents, and select the “InstallESD.dmg” file from it.

Once it is selected, choose “Extract Selected” from the bottom-left. Save it to ~/Downloads/ (it won’t be staying there long).

Ok, this part could be confusing…

When The Archive Browser exports the file, it will not just export the “InstallESD.dmg” file. First it creates a folder “InstallMacOSX” and then it created “InstallMacOSX.pkg” inside that folder, and the “InstallESD.dmg” file is put inside the .pkg… but you can’t see it, because the .pkg file won’t let you open it.

That’s OK, because we’re going to use Terminal.app to move the file into place anyway.

First we need to create a directory inside the ‘Install OS X El Capitan.app’ which we previously saved to /Applications/. We’re going to use the same folder for two commands and we want to make sure we get it exactly right both times, so we’ll make it a variable:

Then use the variable with mkdir to create the folder:

and then we need to move the “InstallESD.dmg” file into that folder

Note: you probably want to trash the ‘~/Downloads/InstallMacOSX/InstallMacOSX.pkg’ (and its parent folder) now that it is empty, to avoid confusion later

Now if you look at the ‘Install OS X El Capitan.app’ in the Finder, it should show itself as 6.21 GB:

So close, and yet…

VMWare was willing to start trying to make a virtual machine using the app, but it failed when it came to the actual installation part:

I don’t know what to try next. Parallels would not use either the ‘Install OS X El Capitan.app’ or the ‘InstallESD.dmg’ to try to create a new virtual machine.

Update and Solution

I posted a question on the VMware Fusion support forum asking how to do this, and someone came up with a very clever solution, which I will replicate here in case others are interested. The idea is simple, but I never would have thought of it.

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  1. Create a virtual machine of any version of macOS, even the current version that you are using on your Mac.
  2. Inside the VM, download the .dmg (see below) and mount it.

  3. Launch the .pkg inside the .dmg.

  4. The .pkg seems to understand that it is inside a VM, and will install the app, which it would not do outside of the VM. Note that the Installer.app says that it will only take a few megabytes, but that is incorrect.

  5. Find the “Install OS X El Capitan.app” (or whatever the app name is) in the /Applications/ folder inside the VM. It should be over 6 GB in size.

  6. Copy the “Install….app” from the VM out to your actual Mac.

  7. Create a new VM using the “Install….app” from the /Applications/ folder on your Mac.

Step #4 is the part that I never would have guessed. The .pkg would not install the app outside of a VM, but will install it inside of a VM.

This worked perfectly with the El Capitan .dmg file, and I’m currently doing the same with Yosemite and Sierra. Then I’ll try the older versions of Mac OS X from old installers that I have from before they disappeared from Apple’s servers.

Update 2

Turns out that Rich Trouton wrote about this technique back in early 2017:

Create Dmg Image Mac Os X 10.10

But I wasn’t working with VMs at the time, so I must not not stored that in my long-term memory.

Update 3

I had saved the older installers for Lion, Mountain Lion, and Mavericks, which are no longer available for download.

Each of them still installed as a VM. Apparently they were not signed with the certificates that expired.

Create Dmg Image Mac Os X Download

Older versions of Mac OS X (10.6.8 and before) are not available to virtualize.