Follow the steps to Mount DMG files in VirtualBox in Windows Host. Its not straight forward as mentioned in title. DMG files can’t not be mounted in Windows 7 VirtualBox directly. First convert it to ISO and mount.
The favorite software I use to convert DMG to ISO is dmg2iso. I tried MagicISO and some other software, but this dmg2iso worked well for me.
Download dmg2iso (dmg2img) here for Windows.
Installation not required, extract the zip file add the dmg2img.exe path in Windows path variable.
Syntax is dmg2img < Source file.dmg> <destination file.iso>
Successful conversion will start and run like shown below.
If DMG file is clean, it will produce ISO file. Mounting this ISO file which came from DMG is easy in VirtualBox. Go to Virtual media manger in VB and add ISO file under CD/DVD images.