Microsoft KB Archive/290526

= Understanding the auto-repair feature of Windows Installer for Office XP =

PSS ID Number: 290526

Article Last Modified on 9/13/2004

-

The information in this article applies to:


 * Microsoft Office XP Professional
 * Microsoft Office XP Professional with FrontPage
 * Microsoft Office XP Small Business
 * Microsoft Office XP Standard

-



This article was previously published under Q290526





For a Microsoft Office 2003 version of this article, see 822238.

IN THIS TASK

 * SUMMARY
 * ** Components and Features
 * Keypath
 * Run-Time Repair
 * Auto-Repair Example



SUMMARY
Microsoft Office XP takes full advantage of the self-repairing features offered by the Windows Installer. If a critical resource is missing, such as a file or registry key that is required to start an Office program, the Windows Installer detects this and repairs the program. If your source files are accessible, you see a Windows Installer dialog box appear briefly during the repair process, and then the program finishes starting.

This articles gives an overview of how the auto-repair process works.

back to the top

Components and Features
The mechanism by which this auto-repair process occurs is based on two building blocks of the Windows Installer: components and features. The smallest and most fundamental block is components, a collection of files, registry keys, and other resources that are all installed or uninstalled as a unit. Features are the granular pieces of a program that you can choose to install. Features typically represent the functional features of the program. Essentially, a feature is a grouping of components. When you perform a Custom installation, the items listed in the Microsoft Office XP: Selecting Features dialog box are the features for Microsoft Office and the Office programs.

back to the top

Keypath
One of the resources within a component can be designated as the keypath for the component. Typically, a file is chosen as the keypath, but the keypath can also be a registry value.

The keypath represents the following:
 * The path to the given component

When a program requests a path to a component, the Windows Installer returns the path to the keypath resource.
 * Verification of whether the component is correctly installed

If the keypath resource is missing, the Windows Installer treats the whole component as broken.

back to the top

Run-Time Repair
The Windows Installer enables a dynamic repair of a program in much the same way that it enables the installation of features on first use. When a program is started, the Windows Installer verifies that each component is correctly installed. As mentioned earlier in this article, the existence of the keypath is used to determine whether a component is broken. If the keypath resource is missing, the Windows Installer automatically reinstalls the component or components that are broken.

back to the top

Auto-Repair Example
The following example demonstrates how the auto-repair process of the Windows Installer can be triggered:
 * 1) You install Office XP, including the Office Shortcut Bar (OSB).
 * 2) You set up the OSB so that it starts each time that you start Windows.
 * 3) After you use Office for a few days, someone deletes Msoffice.exe (one of the files needed to run the OSB) from your hard disk.
 * 4) The next time you start Windows, you expect the OSB to start. However, you see the Windows Installer dialog box appear for a few seconds, and then the OSB starts.

In this scenario, the shortcut to OSA.exe in your Windows Startup folder tries to start the OSB, but it fails because Msoffice.exe is missing. Because Msoffice.exe is a keypath for one of the components (Global_Office_OSB) of the OSB feature (OSBShortCutFiles), the Windows Installer sees it as a broken component. Therefore, it automatically reinstalls the resources in that component, and another attempt is made to start the OSB. Because all of the components have been repaired, the OSB starts.

NOTE: The preceding auto-repair steps do not work on a computer that does not have the Windows Desktop Update installed. Some auto-repair does take place on non-Desktop Update computers, but it is limited. To have complete self-repairing capabilities, at a minimum you must have Internet Explorer 4.01 and SP-1 (or SP-2) and the Windows Desktop Update installed before you install Office XP. This should only be an issue on computers that are running Microsoft Windows NT 4.0, because all other operating systems required for Office XP include the necessary version of Internet Explorer.

back to the top

Additional query words: OFFxp auto-repair self-heal self-healing self-repair auto repair repairing self inf

Keywords: kbHOWTOmaster kbhowto KB290526

Technology: kbFrontPageSearch kbOfficeSearch kbOfficeXPPro kbOfficeXPProFrontpage kbOfficeXPSearch kbOfficeXPSmBus

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.