Can I delete .dmg files after installing an app?
Safe to delete; it rebuilds itself. A .dmg file is the disk image an app arrives in. Once the app is in your Applications folder, the .dmg is a spare copy of the installer, and you can download it again from the maker's website if you ever need it.
At a glance
| Owner app | Finder |
|---|---|
| Typical size | 50 MB–1 GB each |
| Safe to delete? | Rebuilds itself |
| Comes back? | No. Only if you download the installer again |
| What you lose | Nothing installed. You lose the installer file itself, which the maker's website usually offers again. |
| Where it is | ~/ |
What it is
A .dmg is a disk image: a single file that opens like a small removable disk. Apps that you download from a website, rather than the App Store, usually come this way. You open it, drag the app into Applications, and the job of the .dmg is done.
macOS does not remove the file afterwards, so it stays in Downloads. Each one is the full size of the app, often hundreds of megabytes, and after a few years of updates and trial apps they add up to several gigabytes. On the Mac we checked, three recent installers in Downloads took 840 MB.
Deleting a .dmg does not affect the installed app. If you ever need the installer again, the maker’s website has the current version. Gigabroom lists these files in Downloads and moves the ones you choose to the Trash, so you can put them back until you empty it.
Delete it by hand
- If the disk image is still open, click the Eject button next to it in the Finder sidebar.
- Open the Applications folder and make sure the app is there.
- In Downloads, choose View › as List and sort by Kind to see all Disk Images together.
- Select the .dmg files you no longer need, choose File › Move to Trash, then empty the Trash.
With Gigabroom
- Open Gigabroom and wait for the scan.
- In Clean Up, open Downloads. Each .dmg in your Downloads folder is listed as App installer disks, with its size.
- Untick any installer you still want to keep, then click Clean Up. The files go to the Trash, and Put Back is available until you empty it.
Related folders
| Folder | Safe to delete? | Typical size |
|---|---|---|
~/ | Rebuilds itself | — |
~/ | Check first | — |
~/ | Check first | — |
~/ | Check first | — |
Questions
How do I know the app is really installed?
Look for it in the Applications folder. If you opened the app straight from the disk image and never dragged it to Applications, it is not installed, and deleting the .dmg removes your only copy. Drag the app to Applications first.
Why can't I move the .dmg to the Trash?
It is probably still open. Eject it in the Finder sidebar, or quit the app if it is running from the disk image, then try again.
Will deleting the .dmg uninstall the app?
No. The app in Applications is a separate copy. Deleting the disk image does not touch it, its settings or its documents.
Should I keep installers for apps I paid for?
Usually not. Most makers let you download the current version again from your account. Keep one only for an old version you can no longer get.
Last checked on macOS 27.0.1 · 2026-11-10