How to Make a DMG File on a Mac

An easy-to-use guide to making Disc Image files on your Mac computer

Co-authored by wikiHow Staff

Last Updated: September 17, 2024 Approved

One way to store or group files on a Mac is to create a Disk Image. A Disk Image is a file which has the properties of a separate hard drive or CD and allows for greater password protection and compression. To make a DMG file on a Mac, open the Disk Utility app and select New Blank Image.

Manually Creating a DMG File

To create a Disk Image file, create a new folder for your files. Open the Disk Utility application and select New Image > Blank Image….

For popular FAQs on making DMC files jump to more common questions.

Method 1

Method 1 of 2:

Creating a DMG File Manually

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Place the files you would like in your disk image into this new folder for easy access later in the process.
Note the size of its contents so you can know how large you will need to make your DMG File.

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Go to "Applications" and then "Utilities." "Disk Utility" will show up in the dropdown menu.
You can also accomplish this by selecting "File," "New," and then Blank Disk Image." Enter a name for the Image and identify the size you would like for the DMG File. It only needs to be large enough to fit the files you are trying to store. Here you will have the option to encrypt the folder. If you do not wish to encrypt the folder, select "None."
This will create the DMG File. You should be able to immediately see it appear on your desktop or in the left-hand column of your finder window. Once you have done so, exit out of Disk Utilities.
You can do this by simply selected the files you want and dragging them to the DMG file.

Method 2

Method 2 of 2:

Downloading a DMG Application

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Manually creating DMG Files is extremely simple, but if you still feel that you would like to explore the option of downloading a DMG application, research the different apps out there and compare their ratings and customer reviews. There are a few options out there that have helped to make the process of creating a DMG File much simpler. If you choose to download a DMG Application, some popular options are iDMG and DropDMG. In this tutorial, DropDMG will be highlighted but the other apps will work similarly.
Drag the application into your "Applications" folder and then double-click it. Once it has launched, press the eject icon next to the app.^{[1]
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This will cause the changes to take effect.
Once you have restarted your computer, you should be able to access the DMG application.
DropDMG automatically converts files into disk images. All you have to do it drag and drop your files into the app and DropDMG will do the rest.^{[2]
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Common Questions: DMG File Formatting

What is a DMG file on a Mac?

A DMG file is a disk image file. This file is primarily used to distribute software in macOS.

How do I create a DMG file with a password?

To add a password to a DMG file, select the Encryption pop-up menu when creating the file. You can select an encryption option there, such as a password.

How do I convert a folder to DMG?

You will need a folder to create a DMG file. Simply open the Disk Utility application and follow the steps above.

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Tips

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.

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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.

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After you add your files to the image, you can unmount it and then click the "Convert" button in the toolbar. This will let you compress the image or change it to read only (or add encryption).

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