Repackaging Repackaging a Windows Installer package involves taking a snapshot of a clean computer (including the registry settings, files, and system settings), installing the software, and then taking a post-installation snapshot of the computer. The repackaging software detects the difference between the two snapshots and creates the necessary installation instructions to reproduce the installation. Any registry changes, files changes, or systems settings that occur during the capture process are included in the installation. Typically, from 30 to 40 processes run on a Windows XP Professional or Windows 2000 Professional computer at any given time. Thus, any one of those processes can modify a system during the installation, and the modification shows up in the repackaged application Repackaging includes irrelevant or unrelated information Repackaging, by design, includes information in the .msi that is not part of the application. For instance, a message beep from an unrelated process might be included in a repackaged application if the process causes a message-beep to occur at the time of the capture. Another example is if you leave an unrelated folder open in Windows Explorer at the time of the capture, the repackaged application would include the entry pointing to the selected folder. While these examples are relatively harmless, others can disrupt the stability and functionality of a system. Clean Computer : Meaning a computer that has only the operating system installed and no other software installed or removed. If the computer is not clean, the repackaging tool cannot detect any files or registry entries that the application requires. As a result, essential files might be left out of the repackaged .msi file, causing the application to break when you install it. Close nonessential services and windows.