DMG and PKG installer files on a Mac: what they are and when to delete them
Updated
Most apps from outside the App Store arrive as a .dmg or .pkg file. Once the app is installed, the installer has done its job, but it stays in Downloads, often taking hundreds of megabytes each.
What a DMG is
A .dmg file is a disk image: a file that macOS opens as if it were a small drive. Double-click it and a new item appears under Locations in the Finder sidebar, usually showing the app and a shortcut to Applications.
- Double-click the .dmg file.
- Drag the app onto the Applications shortcut in the window that opens.
- Eject the disk image by clicking the eject button next to it in the Finder sidebar.
- Open the app from Applications, not from the disk image.
If you open an app directly from the disk image, it runs from a temporary location and may not update or save settings properly. Always copy it to Applications first.
What a PKG is
A .pkg file is an installer package. Double-clicking it opens the Installer app, which walks through a few screens and places files where the developer specified, sometimes in several locations. Apps with drivers, plug-ins or system components often use a package. When it finishes, macOS may offer to move the installer to the Trash.
Find old installers
- Open Downloads and switch to list view with Command-2.
- Sort by Kind to group disk images and installer packages together, or by Size to see the biggest first.
- For your whole Mac, create a Smart Folder with an Any group: Name ends with .dmg or Name ends with .pkg.
Check the Locations section of the Finder sidebar too. A disk image that is still mounted cannot be deleted until you eject it.
Which ones are safe to delete
| Installer | Delete? |
|---|---|
| For an app you installed and can download again | Yes |
| For an app you uninstalled | Yes |
| For an older version you rely on and cannot get again | Keep, ideally on an external drive |
| For paid software with no account or download page | Keep, with the licence details |
| Mounted and still in the sidebar | Eject first, then delete |
Deleting a .dmg or .pkg never removes the app you installed from it.
Check what a package installed
To see which packages macOS remembers installing, run pkgutil --pkgs in Terminal. pkgutil --files followed by a package name lists the files it placed. Both commands only read information. This is useful before removing an app that came as a package, because those often need the developer's uninstaller.
Clear installers with FileSift
FileSift's Clean Up screen lists installers alongside unused apps, duplicates and old screenshots, with the space each group could free. You can review the list, keep anything you want, and move the rest to the Trash after FileSift confirms the count and size. Because removals go to the Trash first, you can put an installer back if you find you still need it. See also how to clean up Downloads.
Common questions
Does deleting a DMG uninstall the app?
No. The app was copied to Applications. The disk image is only the delivery package.
Why can I not delete a DMG file?
It is probably still mounted. Eject it from the Finder sidebar first.
Related guides
- How to clean up your Downloads folder on a Mac
- How to find and remove apps you no longer use on a Mac
- Zip and other archive files on a Mac: open, create and clean them up
- How to free up space on your Mac
- PDF files on a Mac: where they pile up and how to find them
More in File types, or see all guides.