Not necessary to reinstall Service Packs after adding Windows Components

ID: 164
Created: 2005-05-14
Updated: 2005-05-14

In Windows 2000 and later, it is not necessary to reinstall service packs after adding or editing Windows Components (for example IIS or Networking Services). When a Service Pack is installed, Update.exe installs a Layout.inf file. This file makes sure that when you add windows components, the updated version of the file(s) is used. If the updated file cannot be found in the source location of the Service Pack files, the user will be prompted for the source of the Service Pack files.

When you install a Service Pack for Windows 2000, Windows XP or Windows Server 2003, update.exe performs these actions:

• The Layout.inf file is updated with an additional source for the service pack files. When you change or add windows components, the Layout.inf file points to the correct source. The source location is stored in this registry key:
  
  
  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\ServicePackSourcePath
  
  
  The source can be a network share, the Service Pack CD-ROM, or if you installed the service pack using the Express Installation from Internet, it is the %systemRoot%\ServicePackfiles folder.
• The Drvindex.inf file is updated to point to an additional .cab file for drivers updated in the service pack.
• A new SPn.cat file (where n is the number of the service pack) is installed for the updated files. This file replaces any previously installed SPn.cat file that was installed with a hotfix. The SPn.cat file is installed in the %SystemRoot%\System32\CatRoot\{F750E6C3-38EE-11D1-85E5-00C04FC295EE} folder.

Hotfixes do not update the Layout.inf file. So if you add windows components after a hotfix has been installed, you may have to reinstall the hotfix.

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