These advanced steps are primarily for system administrators and others who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install on multiple computers without downloading the installer each time.
Download macOS
- Nov 15, 2018 WizDMG fills a huge gap in Windows not supporting DMG files. It is a desktop utility supporting Windows and Mac. It allows you to directly burn DMG files to disk in order to create a bootable macOS Mojave installer or a boot disk for any macOS version. WizDMG offers an intuitive interface with no clutter and full functionality to handle DMG files.
- Create a blank disk image for storage. 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. This is the name that appears in the Finder, where you. In the Name field, enter the name.
- Aug 21, 2019 Mac OS X El Capitan 10.11.1 DMG Mac. Mac OS El Capitan was released to manufacturing on 20th September 2015, almost three and a half years ago. Its latest version 10.11.6 (15G22010) was released on 9th July 2018, almost 7 months ago.
- How to get Catalina - if you are running Catalina. Open the Mac App Store. Go to the Catalina page, you can click this link to Catalina on the Mac App Store. Now, if you click on Get, your Mac will offer to download the installers.
Find the appropriate download link in the upgrade instructions for each macOS version:
- macOS Catalina, macOS Mojave, and macOS High Sierra download directly to your Applications folder as an app named Install macOS Catalina, Install macOS Mojave, or Install macOS High Sierra. If the installer opens after downloading, quit it without continuing installation.
To get the required installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. Enterprise administrators, please download from Apple, not a locally hosted software-update server. - macOS Sierra downloads as a disk image that contains a file named InstallOS.pkg. Open this file and follow the onscreen instructions. It installs an app named Install macOS Sierra into your Applications folder.
- OS X El Capitan downloads as a disk image that contains a file named InstallMacOSX.pkg. Open this file and follow the onscreen instructions. It installs an app named Install OS X El Capitan into your Applications folder.
Use the 'createinstallmedia' command in Terminal
Mar 23, 2018 Create, compress, expand and split dmg files. Built in burner functionality to burn ISO and dmg files directly to CD/DVD/Blu-Ray. Read Mac multisession and hybrid CDs.
- Connect the USB flash drive or other volume that you're using for the bootable installer. Make sure that it has at least 12GB of available storage and is formatted as Mac OS Extended.
- Open Terminal, which is in the Utilities folder of your Applications folder.
- Type or paste one of the following commands in Terminal. These assume that the installer is still in your Applications folder, and MyVolume is the name of the USB flash drive or other volume you're using. If it has a different name, replace
MyVolume
in these commands with the name of your volume.
Catalina:*
Mojave:*
High Sierra:*
Sierra:
El Capitan:
- Press Return after typing the command.
- When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
- When prompted, type
Y
to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the bootable installer is created. - When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Catalina. You can now quit Terminal and eject the volume.
* If your Mac is using macOS Sierra or earlier, include the --applicationpath
argument, similar to the way this argument is used in the commands for Sierra and El Capitan.
Use the bootable installer
After creating the bootable installer, follow these steps to use it:

- Plug the bootable installer into a compatible Mac.
- Use Startup Manager or Startup Disk preferences to select the bootable installer as the startup disk, then start up from it. Your Mac will start up to macOS Recovery.
Learn about selecting a startup disk, including what to do if your Mac doesn't start up from it. - Choose your language, if prompted.
- A bootable installer doesn't download macOS from the Internet, but it does require the Internet to get information specific to your Mac model, such as firmware updates. If you need to connect to a Wi-Fi network, use the Wi-Fi menu in the menu bar.
- Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.
What Is A Dmg File
Learn more
For more information about the createinstallmedia
command and the arguments that you can use with it, make sure that the macOS installer is in your Applications folder, then enter this path in Terminal:
Catalina:
Mojave:
High Sierra:
Sierra:
El Capitan:

Open DMG File
DMG is used for disk image files on Macintosh computers running Mac OS X. This file extension replaces the older file extension IMG which was discontinued during the release of later series of Mac operating systems. You can open DMG file on Mac, Linux, and Windows operating systems but it will require additional software to be installed on Windows. Note that on Windows and Linux you cannot open every DMG file, since there are certain software limitations on DMG format variation.
How To Install Dmg File
DMG files are used by Apple for software distribution over the internet. These files provide features such as compression and password protection which are not common to other forms of software distribution file formats. DMG files are native to Mac OS X and are structured according to Universal Disk Image Format (UDIF) and the New Disk Image Format (NDIF). They can be accessed through the Mac OS Finder application by either launching the DMG file or mounting it as a drive.
DMG is also referred to as the Apple’s equivalent to MSI files in Windows PC. Non-Macintosh systems may access DMG files and extract or convert them to ISO image files for burning. Several applications are designed to offer this solution for Windows systems.
7-Zip and DMG Extractor are the best options to open DMG file on Windows because they are compatible with the most DMG variations. For Linux a built-in 'cdrecord' command can be issued to burn DMG files to CD's or DVD's.
Aside from the Finder application, you can open DMG files through Apple Disk Utility, Roxio Toast, and Dare to be Creative iArchiver for Mac platform. On the other hand, additional applications such Acute Systems TransMac, DMG2IMG, and DMG2ISO can be installed on Windows to fully support the files.
Read how you can open DMG files on Mac OS, Windows and Linux.
Creating Macos Dmg File On Mac Computer
DMG files are transferred over e-mail or internet using application/x-apple-diskimage multipurpose internet mail extensions (MIME) type.
Creating Macos Dmg File On Mac Windows 10
Following file types are similar to DMG and contain disk images:
- ISO File - ISO disk image file
- IMG File - IMG disk image file
- VHD/VHDX File - Virtual Hard Drive image file