How to Open and Work With a DMG File in Windows
The first assumption of many people upon seeing a file with the extension “.DMG” is that it’s a damaged file of some kind. However, that’s not the case. DMG files are image files from the Mac OS X used to clone hard drives. It’s the Apple equivalent of an .ISO file in Windows. It’s a compressed file image containing the files necessary for an OS X installation and/or application installations.
The best way to open a DMG file is of course by using a Mac. On a native Mac, you just navigate to the file and mount it. OS X will treat the file as though it were a removable drive and allow you to read from it normally. If for some reason you want to open a DMG file in Windows, however, things are a little different.
Open a DMG file in Windows
If you want to peek inside a DMG file, you will be able to. You won’t be able to do much with what you find though as OS X and Windows are completely different and largely incompatible with each other. Nevertheless, we all love a mystery!
- Download and install 7-Zip or alternative extractor if you don’t have it already.
- Right click the DMG file in Windows Explorer and select Extract.
- Extract the file somewhere safe. It may take your computer a while to perform this action as the file may be enormous. You’ll also need enough free space on your hard drive.
- Open the folder 7-Zip created to browse the contents.
You won’t be able to do much with the image as it is for Apple but at least you can see what’s there. If 7-Zip struggles to Extract, try right clicking and selecting Open archive option. The first time I tried to extract the file, it couldn’t handle it but as soon as I opened the archive, 7-Zip worked fine.
Convert a DMG file into an ISO
If you want to be able to really access the contents of the DMG file on a Windows computer, you need to convert it into an ISO. Then you can mount it as normal using your ISO program of choice. To do this you will need a conversion tool such as AnyToISO, WinArchiver or PowerISO. There are others around I’m sure but these are the ones I know.
I used AnyToISO, so these instructions relate to that package. Others will be similar.
- Download and install your converter of choice.
- Right click the DMG file and select ‘Convert to …iso’. The filename will depend on what your DMG file is called.
- Tell the program where to store the ISO and select Start.
- Allow the program to convert the file. It can take as little as 10 minutes or longer depending on the size of the file and speed of your computer.
If you use PowerISO, the process is very similar.
- Download and install PowerISO.
- Open it, select Tools and Convert.
- Set the DMG file as the source and set a destination.
- Select OK to begin the process.
Once the process completes, you should have a fully working ISO file that you can mount within Windows. You should be able to see what the file contains and check file sizes and properties. However, you won’t be able to do anything with the contents as they will not work in Windows.
Now you have an ISO, you can mount it within a VM and attempt to load a MAC OS virtual machine. This will only work if the DMG was a complete image file and not damaged or missing any components. You will only really find that out when you try to install it. There are better ways to load Mac OS X onto a VM but this one will work if the DMG file is complete.
You won’t often come across DMG files in Windows unless you’re trying to create a hackintosh or Apple virtual machine. However, if you do come across one of these files on your travels as least you now know what to do with it!
Have any other techniques for working with DMG files on Windows? Share them with us below!