Understanding Windows Update Setup

To better understand how to customize the setup process, it is helpful to learn how Windows Update Setup works.

Windows Update Setup is designed to minimize the download time and to recover by itself if it is interrupted - for example, if an Internet connection is broken. This can eliminate the need to run Setup multiple times, which reduces user frustration.

Windows Update Setup (IE5Setup.exe) is small. When the user clicks IE5setup.exe, it causes the .cab files for Internet Explorer and its components to start downloading from the sites specified in the IE5Sites.dat file.

The following is an illustration of how the setup process works.

Illustration 16.2 How Windows Update Setup Works

Windows Update Setup is based on an ActiveX™ engine, which runs on the client computer. The process begins with a small setup package. This self-extracting file can be downloaded to the computer by using an existing browser, or it can be copied directly onto a computer with no existing browser. Because of its swmall size, it downloads quickly or fits on a single floppy disk.

This small setup package also allows Windows Update Setup to collect information about the host computer before the download process begins. Windows Update Setup uses this information to intelligently manage the download of Internet Explorer .cab files and make installation as efficient and problem-free as possible.

While Windows Update Setup is running, log files are created. The Active Setup Log.txt file is a log of the entire setup process from the moment IE5Setup.exe is executed until the download of the last .cab file is complete. When IE5Setup.exe starts, Active Setup Log.txt is created in the C:\ Operating System folder. If an Active Setup Log.txt from a previous Windows Update Setup session exists, it is renamed to Active Setup Log.bak.

The log begins with the date and time the setup program was launched and ends with the date and time it successfully downloads the last .cab file. As the user runs Windows Update Setup, logging entries are continually written to this file. It is the most informative log file for determining what caused a download failure and when the failure occurred. Most entries logged in this file are also written to the registry.

For more information about Active Setup Log.txt, see Appendix B , "Troubleshooting."

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