How the self-repair feature works in Visio

Microsoft Visio takes full advantage of the self-repairing features offered by the Microsoft Windows Installer. If a critical resource is missing, such as a file or registry key that Visio requires to start, the Windows Installer detects this and repairs the program. If your source files are accessible, you may see a Windows Installer dialog box appear briefly during the repair process, after which the program starts.

Components and features

The self-repair process is based on two building blocks of the Windows Installer technology, called components and features.

The smallest and most fundamental block is a component: a collection of files, registry keys, and other resources that are all installed or removed as a unit.

Features are the granular pieces of a program that you can choose to install, and typically represent the features of the program. Essentially, a feature is a grouping of components.

For example, when you perform a custom installation of Microsoft Visio 2002, the items listed in the Microsoft Visio 2002: Selecting Features dialog box are the features of Visio 2002.

Keypath

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

The keypath represents two things:

• 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 properly installed
  
  If the keypath resource is missing, the Windows Installer behaves as if the whole component as broken.

Run-time repair

The Windows Installer enables dynamic repair of a program in much the same way that it enables the installation of features on first use. When you start a program, the Windows Installer verifies that each component is properly installed. As described earlier, the existence of the keypath determines whether or not a component is broken. If the keypath resource is missing, the Windows Installer automatically reinstalls the components that are broken.

To repair Visio by using Maintenance Mode Setup, follow these steps.

Note Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

1. Click Start, click Control Panel, and then click Add or Remove Programs.
2. In the Add/Remove Programs dialog box, click the installed version of Microsoft Visio, and then click Change.
3. Click Reinstall or Repair, and then click Next.
4. Click Detect and Repair errors in my Visio edition installation and click Next.