Apple Disk Image
disk image file format developed by Apple and commonly used by macOS
Apple Disk Image is a disk image format commonly used by the macOS operating system. When opened, an Apple Disk Image is mounted as a volume within the Finder.
An Apple Disk Image can be structured according to one of several proprietary disk image formats, including the Universal Disk Image Format (UDIF) from Mac OS X and the New Disk Image Format (NDIF) from Mac OS 9. An Apple disk image file's name usually has ".dmg" as its extension. A disk image is a compressed copy of the contents of a disk or folder. To see the contents of a disk image, one must first open the disk image so it appears on the desktop or in a Finder window.
Features
Apple Disk Image files are published with a MIME type of application/x-apple-diskimage.
Different file systems can be contained inside these disk images, and there is also support for creating hybrid optical media images that contain multiple file systems. Some of the file systems supported include Hierarchical File System (HFS), HFS Plus (HFS+), File Allocation Table (FAT), ISO 9660, and Universal Disk Format (UDF).
Apple Disk Images can be created using utilities bundled with macOS, specifically Disk Copy in Mac OS X v10.2 and earlier and Disk Utility in Mac OS X v10.3 and later.
The public source identifies “Apple Disk Image” as disk image file format developed by Apple and commonly used by macOS. This brief keeps that definition visible, then builds a research path around Apple, Disk and Image.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Apple Disk Image”, the useful work is to connect “disk image file format developed by Apple and commonly used by macOS” to the records capable of establishing context and consequence.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Aug 13, 2026. The linked authority identifier is Q1228757. None of the 0 selected statements returned an explicit reference.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
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Three-step research path
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- Expand the search: follow Apple Disk Image primary sources, Apple Disk Image archive and Apple research across catalogues and specialist indexes.
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Questions for further research
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This entry incorporates text from “Apple Disk Image” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.