Next, use createinstallmedia utility to copy the installer files to the disk image DMG file you just created:.Hdiutil attach /tmp/MacOSBigSur.dmg -noverify -mountpoint /Volumes/MacOSBigSur Mount the disk image with the following command:.Hdiutil create -o /tmp/MacOSBigSur -size 16500m -volname MacOSBigSur -layout SPUD -fs HFS+J From the command line, create the disk image DMG file destination and temporary volume by issuing the following command:.When the download has finished, open the Terminal application.If you’re already on macOS Big Sur you can re-download the installer with these instructions) Get macOS Big Sur from the Mac App Store (you can download other macOS installers from here if needed.We’re focusing on macOS Big Sur but this approach works with other macOS releases too. We will walk through the process of getting a macOS Big Sur DMG file by building one from the downloaded installer media. Nonetheless, if you’re wanting a macOS Big Sur DMG, here’s how you can get one. For what it’s worth, if you’re looking to create boot media, it’s probably better to simply make a macOS Big Sur bootable install USB drive using the more traditional approach.

Mac disk image cccoma