Mine, being 10.3.9, could only detect that the DMG file was compressed, tried decoding it using ADC decompression, and failed. Format: UDBZ Format Description: UDIF read-only compressed (bzip2) It turns out the DMG file was compressed with bzip2 encoding, which can only be seen/decoded by Mac OS X 10.4+ machines - like my friend's 10.4.8 system. When I failed open the 5.1.26 dmg files, I was thinking maybe this version is corrupted so I try search for older version in virtualbox website and I found version 5.1.22(from old build section) The images in that screenshot mean.dmg files, it's macos term by the way. The file is downloaded from the internet from the software manufacturer’s website and upon mounting the DMG file, a virtual disk is generated from where the user can either copy the application to the applications folder or run an installation script depending on the type of installation. DMG files are used for installing tools and softwares into the Mac OS operating system.
The DMG File format contains data in the form of blocks which are often secured using encryption methods or are compressed using compression algorithms. A DMG File stands for Disk Image file and it is a file format which is used to create mountable disks on the Macintosh operating system.
