Types of images
You use System Image Utility to create network images, which are folders ending with an .nbi extension. Network images contain essential files that start a Mac over an Ethernet network. You can create four types of network images with System Image Utility:
NetBoot
NetInstall
NetRestore
NetInstall network image that contains configuration profiles, scripts, or packages, but no operating system
Using NetBoot, NetInstall, and NetRestore network images, your Mac computers can start from a standardized macOS configuration suited to specific tasks. Because the Mac computers start from the same network image, you can quickly update macOS for users by updating a single disk image or volume.
Open System Image Utility for me
To create network images, see Create network disk images.
NetBoot images
A NetBoot network image allows you to start several Mac computers over an Ethernet network using the NetInstall service of the Server app. Workflows that create custom NetBoot network images can use a bootable volume, a disk image (of a bootable volume), or a macOS install app as the source.
NetInstall images
A NetInstall network image allows you to install macOS on Mac computers. Workflows that create custom NetInstall network images require a macOS install app. After macOS installs, a Mac can start up from its own internal storage device. This network image boots into the installer environment and performs the workflow actions you define.
NetRestore images
A NetRestore network image allows you start up a Mac and quickly replace the entire contents of the internal startup volume. This type of network image can be based on a Mac that’s already configured with preferences, settings, and apps, ready to use, or one that starts up into macOS Setup Assistant. Workflows that create custom NetRestore network images can use a bootable volume, a disk image (of a bootable volume), or a macOS install app as its source. For example, if you create a NetRestore network image of a Mac and at some point the internal storage device on the Mac fails, you can use the image you created to restore the volume on a new internal storage device.
NetInstall images without an operating system
Images without an operating system can contain configuration profiles, scripts, or packages. These images are useful when you want to run a script or install a package on many computers at once. You can also install configuration profiles without using a mobile device management (MDM) solution.
Image contents
NetBoot, NetInstall, and NetRestore network images each contain a disk image and other files necessary for the Mac to start up. You shouldn’t edit these files. Doing so may make the image unusable.
You can set up different NetBoot or NetInstall network images to suit the needs of specific computer models, such as a group for MacBook computers and a group for iMac computers.
For more information, see Create network disk images.