The Microsoft Windows Installer is an application installation and configuration service. WindowsInstaller-KB893803-v2-x86.exe is the redistributable package for installing or upgrading Windows Installer. This revised package replaces the previously released redistributable package named "WindowsInstaller-KB893803-x86.exe" and addresses the issue discussed in KB Article 898628: Windows Installer fails silently after you upgrade to Windows Installer 3.1.