I f you have Windows Installer 3.1 on your computer, then the installation of a Microsoft Windows Installer (.msi) package may fail if the installer attempts to install a more current version of a system file that is being protected by the Windows File Protection (WFP) feature. Additionally, you may notice Windows Installer Error 1931 is added to the Windows Installer log or the Application log Additional Information: WFP is a feature that helps in protecting Windows operating systems and other program files, usually with file name extensions, .dll, .exe, .ocx, and .sys. Some True Type fonts may also be protected by the feature. Primarily, file signatures and catalog files are used to ensure that the files being protected are correct Microsoft versions. WFP allows these files to be replaced only when a hotfix is installed by using the Update.exe or HOtfix.exe, or if the Operating System is upgraded using Winnt32.exe or a Windows Update is performed. Cause of the Error Win...