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.DMG file extension

To open .DMG files on Windows, if you only need to view or extract files from the DMG, use a Windows tool that supports Apple disk images (for example, TransMac per its vendor documentation).

To open a .dmg file on macOS, double-click it to mount it in Finder. On Windows and Linux, you generally need third-party tools to read or extract the contents, and many mobile devices can’t open DMG files at all.

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Last updated: April 30, 2026 · Reviewed by Julian Stricker

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .DMG files

Use these platform-specific instructions to open .DMG files safely.

Windows

  1. If you only need to view or extract files from the DMG, use a Windows tool that supports Apple disk images (for example, TransMac per its vendor documentation).
  2. Open the tool and use its feature to open/browse the .dmg, then extract/copy the files you need to a folder on Windows.
Full Windows guide

Mac

  1. Double-click the .dmg file in Finder to mount it (it should appear as a disk/volume).
  2. Open the mounted volume and follow the app’s instructions (commonly: drag the app to Applications or run an included installer).
  3. When finished, eject the mounted disk image in Finder.
Full Mac guide

Linux

  1. Check your desktop environment’s file properties; many systems identify .dmg as application/x-apple-diskimage via the shared MIME database.
  2. If your file manager can’t open it directly, use a compatible disk-image tool or workflow to extract the contents, or transfer the file to macOS for native mounting.
Full Linux guide

iOS

  1. iOS generally isn’t designed to mount macOS disk images; transfer the .dmg to a Mac to open it in Finder.
Full iOS guide

Android

  1. Android typically can’t mount DMG disk images; transfer the .dmg to macOS to open it, or use a desktop tool to extract files first.
Full Android guide

Security notes

  • Treat DMGs like software installers: a DMG may contain executable macOS apps or installers, so only open disk images you trust.
  • Be cautious of DMGs that prompt you to run an unexpected installer or provide unusual “copy and run” instructions; verify the publisher before proceeding.
  • On Windows and Linux, third-party DMG readers/parsers can have bugs like any file-handling software—prefer well-known tools and keep them updated.

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Can't open this file?

These are the most common causes and fixes when .DMG files fail to open.

Common reasons

  • Double-clicking a DMG does nothing or shows an error (macOS)
  • DMG won’t open on Windows
  • I can open the DMG but can’t use what’s inside

Fix steps

  1. Re-download the .dmg from the original source and try again.
  2. Try mounting it via Finder again; if it still fails, obtain a fresh copy or ask the publisher for an updated DMG.

OS-specific troubleshooting

What is a .DMG file?

A DMG (Apple Disk Image) is a disk image container used by Apple operating systems to package a filesystem into a single file that can be mounted like a disk. When mounted on macOS, it appears as a volume in Finder so you can browse and copy its contents. A commonly used MIME type on desktop systems is application/x-apple-diskimage.

Background

DMG files are widely used in the macOS ecosystem as a convenient way to deliver applications, installers, and bundled resources. Users typically download a DMG, open (mount) it, then drag an app to Applications or run an installer inside it.

On macOS, disk images are handled by the system and are designed to be easy to use from Finder. On other platforms, DMG files are less common, and support varies: some tools can view, extract, or manipulate the image contents, but they may not replicate the full “mountable volume” experience.

On Linux desktops, file type identification often relies on the freedesktop.org shared MIME database, which includes an entry for Apple disk images. IANA’s media type registry is the authoritative place to check whether a media type is formally registered; DMG is commonly seen with an x- prefixed (unregistered) MIME type in practice.

Common MIME types: application/x-apple-diskimage

Further reading

Authoritative resources for more details on the .DMG format.

Common .DMG issues

Double-clicking a DMG does nothing or shows an error (macOS)

This can happen if the download is incomplete/corrupted or if the disk image can’t be mounted by the system.

  1. Re-download the .dmg from the original source and try again.
  2. Try mounting it via Finder again; if it still fails, obtain a fresh copy or ask the publisher for an updated DMG.

DMG won’t open on Windows

Windows doesn’t natively mount Apple disk images, so you’ll need a tool that can read DMG contents.

  1. Use a Windows utility that explicitly supports DMG (for example, TransMac per its documentation).
  2. If you need to install a macOS app from the DMG, use a Mac instead—Windows can’t run macOS apps even if you extract them.

I can open the DMG but can’t use what’s inside

Many DMGs distribute macOS applications (.app bundles) or macOS installers that are not usable on Windows, Linux, iOS, or Android.

  1. Check what the DMG contains (for example, a macOS .app or installer).
  2. If it’s macOS-only software, open/install it on macOS; otherwise, look for a Windows/Linux version from the publisher.

FAQ

What is a .dmg file used for?

It’s an Apple Disk Image, commonly used on macOS to distribute apps and installers as a mountable virtual disk.

How do I open a DMG on a Mac?

Double-click the DMG to mount it in Finder, open the mounted volume to access its contents, then eject it when you’re done.

Can Windows open or install software from a DMG?

Windows can’t natively mount DMGs, and it can’t run macOS apps. Some tools (for example, TransMac) can read or extract files, but installing macOS software requires macOS.

Is the DMG MIME type officially registered with IANA?

A commonly used MIME type is application/x-apple-diskimage; IANA’s media type registry is where you verify whether a type is officially registered versus an x- (unregistered) vendor type.

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