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Types of Servicing

Servicing images means updating an image that is currently available to users — for example, adding an update to your existing image. There are two types of image servicing:

  • Offline. In the context of updating images, the term "offline" refers to updating or applying changes to an operating system image that is not currently running. For example, you might update a .wim file with security updates by using ImageX, while it sits in a folder structure or another partition.

  • Online. In the context of updating images, the term "online" refers to updating or applying changes to an operating system that the computer is booted into. For example, installing an update by using Windows Update is an online operation.

Windows Vista supports offline servicing of images that have been prepared with Sysprep, whereas earlier versions of Windows do not. You can service an image offline with Package Manager or on a running Windows operating system with OCSetup, Package Manager, or the Windows Update Standalone Installer. Package Manager works only with operating system packages (hotfixes, updates, drivers, service packs, and language packs). All of these are command-line tools can install and uninstall packages. Service packs and other updates that are delivered as .msu files must be installed online on a running Windows installation with the Windows Update Standalone Installer. For more information, see Servicing an Image (

Servicing an Image Offline

The following are the four high-level steps you will need to perform to service an image offline.

  1. Disable the current image. To do this, right-click the image and click Disable. This allows currently connected clients to finish applying the image, but it prevents new clients from starting an installation.

  2. Export the image to a location outside of the image store. To do this, right-click the image and click Export. For install images, this combines the metadata in the install.wim file with the resources in the Res.rwm file into a single .wim file and saves it to the destination location. To save space, you can also use the WDSUTIL /Export-Image command to append the images to an existing .wim file. This is also generally faster than exporting it to a new .wim file. For more information about this command, see /export-Image.

  3. Service the image. In this step, you update the image using the tools in the Windows AIK. For example, you can mount the image to a folder by using ImageX, and then add the files and folders to the image. You can also load the registry hive to add, delete, or modify registry keys. If the image is a boot image, you can use PEimg.exe to add drivers to the image. After all your changes are complete, use ImageX to commit the changes to the .wim. For more information, see the following topics:

  4. Replace the current image with the updated version. In this step, you add the updated image back to the Windows Deployment Services server. If the previous image is still in use, you have two options:

    • Wait for existing installations to complete, delete the old copy, and then replace it with the new. To do this, right-click the image and click Replace. We recommend this method because any associated external data such as language packs, unattend files, or $OEM$ folder contents will remain associated with the image.

    • Add the updated image as a new, separate image. You must also copy or associate any external data such as language packs, unattend files, or $OEM$ folder contents.

Sometimes it may be more efficient to redeploy and recapture an image to add applications, rather than servicing the image offline.

Reducing the Size of Images

An image group is a collection of images that share common file resources and security. The following are the two components of an image group:

  • Res.rwm file: Contains the file resources for each image group.

  • Image.wim files: Contains the metadata that describes the content of the install image.

Because the images are stored this way, removing an image from an image group does not reduce the size of the files. This is because files in the Res.rwm file that no longer belong to an image are not actually converted to free space; rather, they are just dereferenced. To reclaim free space within the Res.rwm file, you must perform the following steps:

  1. Export all images from the image group to an external .wim file.

  2. Create a new image group.

  3. Add all exported images to the new group.

When performing this procedure, you must manually copy and reassociate any external data (such as language packs and unattend files) to the new image group.