Can You Delete DMG Files After Installing on Mac?

Short answer: yes. Once an app is in your Applications folder, the .dmg it arrived in is dead weight — a shipping box you never threw out. Downloads folders routinely hide gigabytes of them. Here's why they're safe to delete, and the one step to do first.

A DMG is just the delivery box

A .dmg file is a disk image: a container format developers use to ship apps outside the App Store. Double-clicking one mounts it as a virtual, usually read-only volume — it shows up in the Finder sidebar and often opens a window telling you to drag the app into Applications.

That drag is the actual installation. It copies the app out of the image and onto your disk. From that moment the DMG serves no purpose: the app doesn't reference it, updates don't need it, and uninstalling doesn't involve it. Deleting the DMG cannot break the installed app, on any version of macOS. The only real cost of keeping them is disk space — some app images run into hundreds of megabytes each.

Eject first, then delete

1. Check the Finder sidebar (and your desktop) for the mounted image — it appears under Locations with an eject symbol next to it. Click ⏏, or right-click it and choose Eject.
2. In Downloads, drag the .dmg file to the Trash.
3. Empty the Trash when you're ready — that's when the space actually comes back.

If macOS refuses to eject with a "volume is in use" error, the usual culprit is the classic mistake: the app was launched straight from the DMG window and is still running from inside the mounted image. Quit the app, copy it into Applications properly, launch it from there once, then eject and delete. Since the file only moves to the Trash, you can put it back at any point before emptying — that's your undo.

Find every DMG at once

One-at-a-time cleanup misses the years of backlog. Round them all up:

• In Finder: open Downloads, press Cmd+F, and search for dmg with the criteria set to file name. Save the search as a Smart Folder if you want a recurring sweep you can revisit.
• In Terminal, list every DMG in your home folder, biggest first:

# list all .dmg files with sizes, largest at the top (read-only)
find ~ -name "*.dmg" -exec du -h {} + 2>/dev/null | sort -rh | head -20

The command only lists files — it deletes nothing, so there's nothing to undo. Delete the ones you don't want via Finder rather than rm, so they land in the Trash and stay recoverable until you empty it. The same logic applies to .pkg installers and the .zip archives apps sometimes ship in: once the app is installed and working, the wrapper is disposable.

The few worth keeping

• Apps that are no longer distributed — abandoned software you can't download again.
• Old versions you deliberately stay on, when the vendor only serves the latest release.
• Huge downloads on slow or metered internet, if you expect to reinstall soon.

Everything else — browsers, editors, utilities from active vendors — is a fresh download away. Archive the rare keepers to an external drive and clear the rest with a clean conscience.

While you're in Downloads anyway

DMGs are rarely the only junk in there — old installers, duplicate photos, and forgotten zips pile up alongside them. Our guide to cleaning the Downloads folder on Mac covers a full sweep, including a sort order that surfaces the biggest offenders first.