The Microsoft policy for disk duplication of Windows installations

When you deploy a duplicated or imaged Windows installation, it is required that the System Preparation (Sysprep) tool is used before the capture of the image. Sysprep prepares an installation of Microsoft Windows for duplication, auditing, and customer delivery. For Microsoft Windows 2000, Windows XP, and Windows Server 2003, Sysprep is included with the latest service pack Deploy.cab. For later versions of Windows, Sysprep is included with the operating system, and Sysprep is located in the following folder:

Sysprep is responsible for removing system-specific data from Windows, such as the Computer SID. During installation of Windows, a computer SID is computed to contain a statistically unique 96-bit number. The computer SID is the prefix of the user account and group account SIDs that are created on the computer. The computer SID is concatenated together with the Relative ID (RID) of the account to create the account's unique identifier.

The following example displays the SIDs for four local user accounts. Notice that only the last four digits are incremented as new accounts are added. Cloning or duplicating an installation without taking the recommended steps could lead to duplicate SIDs. For removable media, a duplicate SID might give an account access to files even though NTFS permissions for the account specifically deny access to those files. Because the SID identifies both the computer or domain and the user, unique SIDs are necessary to maintain support for current and future programs.

In addition to the computer SID, many other components and features must be cleaned up, generalized, or specialized in order to be imaged. Some examples include the following:

• Event logs
• Network settings
• Windows Media player settings
• Shell settings
• Licensing

Note This is not a comprehensive list.

We support the following operating systems that are prepared by using the Sysprep utility and then imaged:

• Windows NT Workstation 4.0
• Windows NT Server 4.0 (stand-alone server, not primary domain controllers or backup domain controllers)
• Windows 2000 Professional
• Windows 2000 Server (must be imaged before you run DCPromo)
• Windows 2000 Advanced Server
• Windows XP Home Edition
• Windows XP Professional
• Windows Server 2003, Standard Edition
• Windows Server 2003, Datacenter Edition
• Windows Server 2003, Enterprise Edition
• Windows Server 2003, Web Edition
• All versions of Windows Vista
• All versions of Windows Server 2008
• All Versions of Windows 7
• All versions of Windows Server 2008 R2

We do not provide support for computers that are set up by using SID-duplicating tools other than the System Preparation tool. For example, this includes the following:

• NewSID (http://technet.microsoft.com/en-us/sysinternals/bb897418.aspx)
• GhostWalker (http://service1.symantec.com/SUPPORT/on-technology.nsf/docid/1999050308324125)

Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

Note If an image was created without using Sysprep, we do not support the running of Sysprep after the image is deployed as a way to bring the computer back into compliance. Sysprep must be run before the capture of the image.

For more information about the Windows System Preparation Tool, visit the following Microsoft websites:

Windows XPWindows Server 2003Windows 7
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.