As you can see in my screenshot, when browsing from the VirtualBox medium finder, Explorer lists DMG in the supported file types section.

During the installation, the program will declare which file types it supports.

In this case we can see the VirtualBox has declared support for DMG format.

Dmg File Extension Mac OS X Setup Package

However, an InstallESD.dmg image from a Mac OS X setup package worked just fine and booted in Virtualbox on a Windows 7 host.

I tried to connect a Fat32 USB stick image and it says corrupted file system.

DMG files are raw disk images that contain block data and may have one or two additional layers applied to add encryption and compression.

These layers are identified in the hdiutil command line as CEncryptedEncoding and CUDIFEncoding.

DMG files are mostly used as software installers for the Mac OS platform.

How to open DMG Files When opened in Mac OS the Disk Image is mounted as a volume that can be accessed within the Finder.

DMG files are not intended to be used with Microsoft Windows or any other Operating System.

However, there are programs that can be used to open and convert some DMG files to an extension that is usable with Microsoft Windows or Linux.

You might need to purchase certain software to do the actual conversion.