.DMG File Extension

Mountable disk image created in Mac OS X; contains raw block data typically compressed and sometimes encrypted; commonly used for Mac OS software installers that are downloaded from the Internet; mounts a virtual disk on the desktop when opened.

The DMG format replaces the older .IMG file format, which is used in Mac OS Classic and is not compatible with Mac OS 9 and earlier. DMG disk images can be opened using the Apple Disk Utility that is bundled with Mac OS X on Apple computers.

DMG files are Mac-specific and are not intended for use in Windows. However, Windows Daemon Tools may be able to mount virtual drives from some DMG image files. Other utilities may also be able to convert DMG files to a format that can be recognized by Windows.