FastDMG

"Replaces the system default DMG mounting application; is better in every way."
- Max Masnick

FastDMG is a free macOS utility to mount .dmg and other disk images quickly and efficiently, without any unneeded nonsense. It is a very fast and reliable alternative to Apple's annoying DiskImageMounter.

Features

• Doesn't waste your precious time verifying disk images
• Auto-accepts annoying end user license agreements
• Runs in the background (doesn't show up in the Dock)
• Displays no windows or menus and stays out of your way
• Multithreaded, can concurrently mount several images
• Disk image document icons continue to look the same
• Handles all disk image types supported by DiskImageMounter (dmg, iso, toast, etc.)
• Very fast native app written in Objective-C/Cocoa

FastDMG is actually a minimal wrapper around the hdiutil command line tool that ships with macOS and therefore uses Apple's private DiskImages framework indirectly.

I've personally used FastDMG for over a decade and it works really well. It's solid, free, open source software and has a home on GitHub. If you like it, feel free to make a donation.

Download

• ⬇ Download FastDMG 1.0.3 (~1.3 MB, Universal ARM/Intel 64-bit, 10.13 or later, Developer ID signed and notarized by Apple)

Older versions are available here.

How to use

• Move FastDMG.app to your Applications folder
• Ctrl-click the FastDMG app and select Open to bypass Apple's Gatekeeper
• Select a .dmg file in the Finder and press Cmd-I to show the Get Info window
• Select FastDMG under "Open with:"
• Press "Change All..."

FastDMG will then take care of mounting .dmg disk images when they're opened in the Finder. You can do the same for .iso, .toast and any other disk images supported by FastDMG.

Version History

1.0.3 - 20/05/2025

• App is now Developer ID signed and notarized by Apple
• New application icon by maxtron95

1.0.2 - 28/11/2020

• App is now built as a Universal ARM/Intel 64-bit binary

1.0.1 - 07/04/2019

• App is now Developer ID signed
• Now built with support for Mojave Dark Mode

1.0 - 23/05/2018

• Initial release