DMG is a macOS disk image file used to distribute software — it mounts as a virtual drive on your desktop, typically containing an app you drag to your Applications folder.
Use caution
Type System
By Apple
MIMEapplication/x-apple-diskimage
Drop any file to identify it
We read file headers, not extensions. Nothing gets uploaded.
DMG is a macOS disk image file used to distribute software — it mounts as a virtual drive on your desktop, typically containing an app you drag to your Applications folder. Mac's weird way of installing software. On Windows, you run an installer. On Mac, you open a DMG. Inside, you'll usually find an app icon and an arrow pointing to your Applications folder. Drag, drop, eject, done. It's elegant once you understand it and baffling the first three times. The format supports compression, encryption, and checksumming, which makes it ideal for distributing verified software. Despite the rise of the Mac App Store, most third-party developers still ship their apps this way. If you're on Windows and someone sends you a DMG, 7-Zip can extract its contents.
Technical details
Full Name
Apple Disk Image
MIME Type
application/x-apple-diskimage
Developer
Apple
Magic Bytes
78 01 73 0D
Safety
.dmg requires caution. DMG files can contain any software. Only open DMGs from trusted developers. macOS Gatekeeper will warn you about unsigned apps.
What opens it
macOS (mounts natively)
FREEmacOS
7-Zip
FREEWindows
* Can extract contents
FAQ
How do I open a DMG file on Windows?
Windows can’t mount DMGs natively. Use 7-Zip (free) to extract the contents. HFSExplorer (free) also works. Keep in mind that .app bundles inside are macOS-only — you can extract assets but not run Mac software on Windows.
What is the difference between DMG and PKG?
A DMG is a disk image — it mounts as a virtual drive and usually lets you drag an app to install it. A PKG is a macOS installer package that runs a step-by-step installation process, often used when an app needs to install system extensions or components in multiple locations.
What do I do after mounting a DMG?
Drag the application icon into your Applications folder. Then eject the DMG by right-clicking its icon on the desktop or sidebar and selecting Eject. You can delete the original .dmg file after installation — the app has already been copied.
Are DMG files safe to open?
DMG files themselves are just containers — the safety depends on what’s inside. macOS Gatekeeper checks for developer signatures and notarisation. If you see a warning that the app is from an unidentified developer, be cautious. Only open DMGs from sources you trust.