Before you begin
Each release of macOS has both a version number (like 10.12) and a build number (like 16A323). Some versions of macOS have more than one available build. For example, when you purchase a new Mac, it comes with a model-specific build of macOS. This build might be newer than the build of macOS that's available from the Mac App Store, even if the version numbers are the same.
When creating a system image for multiple Mac models, it's important to use both a version and build of macOS that works every Mac you want to support. If you try to use an older version or build of macOS than what came with a Mac, it might start up to a prohibitory symbol, or exhibit other unexpected behavior.
You can check these things to make sure the image you're creating or using works with your Mac:
- Check the version and build of macOS that came with your Mac.
- Check the system requirements for the reference release of macOS you want to use to make sure this version of macOS works with your Mac.
- Check the build number of the version of macOS available from the Mac App Store.
- Make sure that the macOS build you place on your image is the same or later than the one that came with your Mac.
Create a NetBoot or NetRestore Image by downloading the latest installer
In OS X Lion and later, you can create a NetBoot or NetRestore image that supports multiple Macs by using the latest version of the macOS Installer from the Mac App Store.
- Start from a Mac that supports the version of macOS you're trying to download (like macOS Sierra).
- From the Apple menu, choose App Store.
- Click the Purchases icon.
- Click the Download button next to the macOS Installer you want to download.
If you don't see the software you want, check these things:
- If you're trying to download an older version of macOS, make sure you're logged into the App Store using the Apple ID you previously used to purchase that version of macOS. Older versions of macOS are only available from the Purchases pane if you purchased them previously.
- Check to make sure the Mac you're trying to download from supports the version of macOS you're looking for. For example, you can't download the installer for OS X El Capitan if you're viewing the Purchases pane from a Mac that came with macOS Sierra.
- Check to make sure you don't have hidden purchases.
If you have an existing image that you want to update, use the macOS Installer from the Purchases pane, or the manual updater instead of updating the volume from the Updates pane of the Mac App Store.
Create a NetBoot or NetRestore image using a startup disk
If your Mac came with a build of macOS that is newer than what is currently available from the Mac App Store, you can create an image using the startup disk from that Mac.
Configure your image
You can restrict access to images based on the computer model to prevent users from starting from an unsupported version of macOS on their Mac.
- If you're creating a new image you can use System Image Utility to restrict which models of computers are allowed to start from a specific image. Refer to the System Image Utility Help for more information about configuring the Filter Computer Models workflow action.
- If you've already created an image, you can use Server app to restrict which models of Mac computers are allowed to start up from a specific image. When viewing the list of images in Server app, select an image, then press the Edit button to configure filtering options.