Before you begin
Each release of OS X has both a version number (like 10.10.3) and a build number (like 14D136). Some versions of OS X have more than one available build. For example, when you purchase a new Mac, it comes with a model-specific build of OS X. This build might be newer than the build of OS X that's available from the Mac App Store, even if the version numbers are the same.
The About This Mac window on this Mac shows a version number of 10.10, and a build number of 14A389.
When creating a system image for multiple Mac models, it's important to use both a version and build of OS X that works with all of the Macs you want to support. If you try to use an older version or build of OS X 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 OS X that came with your Mac.
- Check the system requirements for the reference release of OS X you want to use to make sure this version of OS X works with your Mac.
- Check the build number of the version of OS X available from the Mac App Store.
- Make sure that the OS X build you place on your image is the same or later than the one that came with your Mac.
For example, If you have an iMac (Retina 5K, 27-inch, Late 2014) you can use an image that contains one of these builds:
- OS X Yosemite v10.10.2 image with build 14A389 or build 14C109
- OS X Yosemite v10.10.3 with build 14D131
This image also works with any Mac that supports OS X v10.10.3 that didn't come with a newer build of OS X.
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 OS X Installer from the Mac App Store.
- Start from a Mac that supports the version of OS X you're trying to download (like OS X Yosemite).
- From the Apple menu, choose App Store.
- Click the Purchases icon.
- Click the Download button next to the OS X 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 OS X, make sure you're logged into the App Store using the Apple ID you previously used to purchase that version of OS X. Older versions of OS X 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 OS X you're looking for. For example, you can't download the installer for OS X Lion if you're viewing the Purchases pane from a Mac that came with OS X Yosemite.
- Check to make sure you don't have hidden purchases.
If you have an existing image that you want to update, use the OS X 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 OS X 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.
Create a NetBoot or NetRestore images using an updater
In OS X Snow Leopard, you can create a NetBoot or NetRestore image that supports Macs that work with Snow Leopard by installing a reference release and then applying the latest Mac OS X v10.6 combo update.
- A Mac OS X v10.6.7 image created using the combo updater supports all Intel-based Mac models introduced in 2010 or earlier. Models introduced in 2011, such as the MacBook Pro (Early 2011) and iMac (Mid 2011), require a NetBoot or NetRestore image that is based on their computer-specific release.
- A Mac OS X v10.6.8 image created using the combo updater supports all Mac models that support Mac OS X v10.6.x Snow Leopard. This includes support for the MacBook Pro (Early 2011) and iMac (Mid 2011) models.
Even if the system you're imaging has the latest version of Snow Leopard installed, you must update it using the combo updater to create an image that supports multiple Mac computers. You can manually download and re-install the latest combo updater from Apple Support Downloads before creating an image.
Configuring your image
You can restrict access to images based on the computer model to prevent users from starting from an unsupported version of OS X 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 Advanced Administration Guide for OS X Server 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.