What is DMG File And How to Open It

In computing world, DMG or (Disk Image File) is a file extension that belongs to Mac OS X. DMG file can also be termed as Apple Disk Image. The icon used equivalent to this file is an Internal Hard-drive. Disk Images are generally used worldwide in-order to distribute applications and software across the Internet. DMG file provides some attractive features that allow securing password along with file compression.
These virtual or physical Apple disks can be cloned from one to another. This is one of the powerful features of Mac.

Tip: If you want to open and view DMG files of Apple Mac OS X so, you can try DMG Viewer tool.

Why DMG Files Are Created?

Earlier, Mac applications made use of Resource fork. These are the part of file system on Mac Operating System, which consists of both the structured data and non-structured data. Mac could not transfer these Resource forks over the mixed networks. Hence, the usage of Resource fork dwindled and this was the reason that Apple created disk image formats(DMG). The Resource forks are very important as they contain Meta data regarding the file.

Mounting and Dismounting on Mac OS

It is equivalent to plugging in a removable drive, where E drive is automatically created and while removing one chooses ‘Safely Remove Device’. Similarly, you have to eject the Mac drive for both the virtual and physical.
Two Disk Formats supported are:

• NDIF
  This was previously used as the default format of Mac, also known as New Disk Format. These files generally have an .img file extension.
• UDIF
  The native disk format of Apple Mac DMG file is UDIF (Universal Disk Image Format) with a file extension of .dmg.

MIME Type of DMG File:
application/x-apple-diskimage.

Supported File Systems

• Hierarchical File System (HFS) – This was developed by Apple Inc. for the systems supporting Mac OS. Earlier, these file systems were used in floppy disks and hard disks but later were used to read CD-ROM as well. It is known as Mac OS Standard.
• HFS Plus – It was developed after HFS, which is an extension of the same. It is known as Mac OS Extended.
• File Allocation Table (FAT) – It is a file system generally compatible with all file systems and helps in exchange of data between systems.
• ISO9960 – This is also a file system which was issued by ISO (International Organization for Standard) supporting various OS and helps in exchange of data.
• Universal Disk Format –This is a file system usually used to store broadcast media like DVD and optical disk formats.

How to Open DMG Files?

In Mac:

• When you download a Disk image, all the applications in it must be copied to the Application files, because many of these files will be in read-only format. Running these files inside the drives may produce some erroneous results.
• Double clicking the DMG File will open the file and you can view the contents in it. It might be images, documents, programs, etc.
• The DMG File consists of an application file. You can simply drag and drop to install them. If there is a possibility of having an installer, you can run these files instead of installing.
• Right-click on the File >> “Eject” (click on virtual disk instead of, original file)
  Delete the old DMG Files after installing. The reason is old files may take more space when we install new programs.

Resize DMG Files

• Right click DMG File >> Click Get Info (View the original size).
•  Open Disk Utility >>Select Images Tab>Click on Resize>>Select the DMG file to be resized.
• Click on Open >>Type the file size to be reduced>>Select Resize>>Done

In Windows:
Originally, DMG files are the default Disk Image file for Mac. Hence, they can be opened only on Mac OS.
Since there are no manual methods available to view the DMG Files in Windows, users can install external third-party software available online on Internet. DMG Viewer is one of the tools from such category.
The software provides you with the following features:

• Open DMG File in Windows OS based machine
• Read: Corrupt, Password Protected & Encrypted DMG
• Recover permanently deleted files from DMG
• Search a specific file type in large DMG Format Files

Conclusion

Considering the ongoing necessity to view DMG files, we have described a manual process to let the users understand how to open & view DMG files. Else, users can take the help of a reliable third-party tool named as DMG Viewer. It is the best application that helps to read .dmg files in Windows OS. Users can use any approach as per their choice.