DMG (Apple Disk Image)

A DMG (Apple Disk Image, .dmg) is the standard container for distributing Mac apps outside the App Store. Opening one mounts it like a drive and shows the familiar window: your app's icon, an arrow, and an Applications folder shortcut.

The drag-to-Applications ritual isn't just tradition. Apps run from the Downloads folder hit macOS's App Translocation (see Gatekeeper): the OS runs them from a randomized read-only location, which silently breaks self-updating. The DMG's whole job is getting the app into /Applications, where updates and permissions work properly.

A production-grade DMG is code signed and notarized, styled with a background image and positioned icons, and built universal so one download serves Intel and Apple Silicon Macs. Deskifier produces exactly that for every macOS build.