How To Open DMG Files in a Mac® or Windows Operating System

Macs use a specific file extension called a DMG to consolidate files for downloads. You may see this extension on your computer and wonder how to open it. When opening a file extension in a Mac operating system, it's important to understand how this file holds and delivers information so you can access the contents and store transfer files to your computer.

In this article, we explain how to open a DMG file using both the macOS® and Windows operating systems.

What is a DMG file?

DMG files are disk image files used for macOS software, which is used for devices running Mac programming and operating systems. DMG is the new file extension for the previously used IMG, which was part of the Mac OS Classic. Although DMG files can exist in Microsoft systems, they require a special process and a tool to extract the file content.

DMG files typically carry installation software for Mac computer systems. A compressed file used to install operating software, DMG extensions contain applications you can download by dragging and dropping the files into your apps folder.

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Why are DMG files important?

Files in the DMG format offer extra protection to computers. When you download a DMG file, the first thing that happens is a verification scan to ensure that everything contained in the file is free of viruses and not corrupted. They also make the size of a download smaller by compressing the files. Downloading a smaller file can make the process faster and take up less space on your device's memory. DMG files also allow you to skip the step of using a "wizard" to open and install downloaded apps.

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How to open a DMG file in a Mac

Opening a DMG file on a Mac takes a few quick actions once you receive the file. Follow these steps to access your DMG files:

1. Download the file to your device

Choose the file from your email or download it directly from a credible website. Check for the DMG file extension at the end of the file name. Select the file to download it to your computer.

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2. Select the file to open it

Once you download the file, open it to your device. You can do this by double-clicking the DMG file to mount it to your Mac. You can now access the file through your desktop or "Finder" sidebar.

3. Move the file to your applications folder

After you mount the DMG file to your device, drag it to the "Applications" folder on your Mac. The file then copies itself into the folder, so you may have a few moments of lag time. When the file is fully moved into the applications folder, you can open it from the "Spotlight" or "Launchpad" program shortcuts.

4. Launch the app

You're now ready to select and launch the application from the file download. Once the DMG file serves its purpose, it no longer functions. Clicking on the file can't launch any applications because the contents have been moved and copied and the original file is empty after delivering its file load.

How to open a DMG file in Windows

You can still access a DMG file using a Windows operating system with the help of an extraction tool. These applications are often free to download and allow you to use the same files as Mac users. The following steps can help you open this type of file on your Windows device:

1. Choose a downloading tool

You can find plenty of available tools to download DMG files for Windows operating systems. Popular applications like DMG Extractor or 7-Zip allow users to use this file typically formatted for macOS software. It may even be helpful to choose more than one tool to download and use for DMG file transfers since certain applications may not open a selected file.

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2. Open the extraction tool

Once you determine the best application or multiple applications to use for accessing DMG files on a Windows operating system, launch the application. You can now view the contents of the DMG file and choose which files to open through the tool. This also allows you to choose how to open a specific file if you have multiple tools.

3. Select your chosen file and tool

After right-clicking on the file you want to access, choose your extraction tool from the list of options. Once you select the extraction tool, you typically have further options in a drop-down menu. This allows you to choose where you want to save the contents of the DMG file once you extract it. Extraction tools usually give you the option to save the file to a specific location within the DMG files, in a path outside of the file or in a new folder you create.

4. Download the file

It may take some time, but you can now begin to transfer the data from the DMG file to your computer. After the download is completed, look for the file outside of the DMG folder. You can now open the file as a regular item using your Windows operating system.

Tips for working with DMG files

Below are some ideas to help you learn more about using DMG files effectively:

Use it then lose it

Don't plan to open a DMG file after you install a program. It won't be there because the DMG acts as an envelope or shell for delivering the app and becomes empty once the file is extracted. After it performs this function, the file no longer has any use and you can delete the DMG file.

Use the right file

If you're operating on a computer using Windows, look for a similar file called ISO. Using this type of file can avoid the need for extraction tools. You also won't need to download application files in a macOS format. If possible, find files using this file extension instead.

Use DMG files like a flash drive

DMG files operate as if a separate device is delivering information to your computer. Think of this kind of download as a way to avoid inserting another storage system into the computer. A DMG file download may take less time to download than the traditional transfer of information from a flash drive or CD to your device.

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