# Dynamic Update

Microsoft regularly provides reliability and compatibility improvements, and also provides emergency fixes for security issues. Some of these updates might not be available on the Windows XP Professional operating system CD.

Updates are assembled into Dynamic Update packages, which are available on the Windows Update Web service. You can access Dynamic Update packages by selecting Yes, download the updated setup files on the Get Updated Setup Files screen of the Windows Setup wizard. Setup then downloads and installs the updated files instead of using the equivalent files on the Windows XP operating system CD.

### To download the Dynamic Update package

1. From the Windows Update Catalog, click Find updates for Microsoft Windows operating systems.
2. Under Operating system, select Windows XP Home Edition or Windows XP Professional.
3. Click Advanced search options to display additional search criteria.
4. Under Update types, click to select the Service Packs and Recommended Downloads check box, click to clear all other check boxes, and then click Search.
5. Under Your search returned n results, click Service Packs and Recommended Downloads.
6. Under Dynamic Setup Updates, click Add, and then click Go to Download Basket.
7. Type the path to the network share where you want to copy the Dynamic Update package, and then click Download Now.

If a Dynamic Update package is available and you downloaded the package during setup, expand the downloaded package to display the .cab files. The package can contain one of the four .cab files shown in the following figure. The figure shows the structure of the network share folder and the relative location of each subfolder, including two drivers, Drv1.cab and Drv2.cab, that were downloaded.

Network share folder structure

## Processing Dynamic Update .cab files and driver .cab files on the network share

To process the Dynamic Update .cab files and all the driver .cab files that you downloaded from Windows Update, run Winnt32.exe with the /DUPrepare parameter pointing to the location of the downloaded .cab files, as shown in the following example:

`Winnt32 /DUPrepare: path to CAB files`

## Installing the dynamic update package

To install Windows XP Professional and use the processed Dynamic Update .cab files, you can run Winnt32.exe with the /DUShare parameter, or you can specify in your answer file where Setup can find the processed .cab files. When you run Winnt32.exe with the /DUShare parameter, the Dynamic Update wizard is not displayed to the user and no attempt is made to connect to Windows Update.

The update files are copied from the share into the appropriate folders under %windir%\Setupupd. Setup searches the installation media for device drivers. If a device driver is not found, Setup searches the driver folder in the Dynamic Update share. Setup finds and installs a device driver.

### To run Setup and connect to the Dynamic Update Share

At the command line, type:

`Winnt32 /DUShare:path to dynamic update share`

When you run Setup in unattended mode and specify a dynamic update share to connect to, dynamic update is disabled by default; the Dynamic Update wizard is not displayed to the user, and no attempt is made to connect to Windows Update.

### To specify a Dynamic Update share in Unattend.txt

In the [Unattended] section of the Unattend.txt answer file, include the following key and value:

`[Unattended]
DUShare = "Path to dynamic update share"`