Windows Installer

Windows Installer (msiexec.exe, previously known as Microsoft Installer, <a href="/facts/List_of_Microsoft_codenames/r5DHMHhk">codename</a> Darwin) is a <a href="/facts/Software_component/eW5wvSHC">software component</a> and <a href="/facts/Application_programming_interface/GMlN4vUr">application programming interface</a> (API) of <a href="/facts/Microsoft_Windows/bwhAhuSL">Microsoft Windows</a> used for the <a href="/facts/Installation_(computer_programs)/EQzPeYv2">installation</a>, maintenance, and removal of software. The installation information, and optionally the files themselves, are packaged in <a href="/facts/Package_(package_management_system)/kEX4kx7g">installation packages</a>, loosely <a href="/facts/Relational_database/pEKGmJLy">relational databases</a> structured as <a href="/facts/COM_Structured_Storage/QLuCym7S">COM Structured Storages</a> and commonly known as "MSI files", from their default <a href="/facts/Filename_extension/cJgfAym4">filename extensions</a>. The packages with the file extensions mst contain Windows Installer "Transformation Scripts", those with the msm extensions contain "Merge Modules" and the file extension pcp is used for "Patch Creation Properties". Windows Installer contains significant changes from its predecessor, Setup API. New features include a <a href="/facts/GUI/wBlQFWDP">GUI</a> <a href="/facts/Software_framework/EWasA8sG">framework</a> and automatic generation of the <a href="/facts/Uninstallation/q3IUzRUr">uninstallation</a> sequence. Windows Installer is positioned as an alternative to stand-alone executable installer frameworks such as older versions of <a href="/facts/InstallShield/1hFpJR0S">InstallShield</a> and <a href="/facts/Nullsoft_Scriptable_Install_System/j3tNXcch">NSIS</a>.
Before the introduction of <a href="/facts/Microsoft_Store/tnnWFhAF">Microsoft Store</a> (then named Windows Store), Microsoft encouraged third parties to use Windows Installer as the basis for installation frameworks, so that they synchronize correctly with other installers and keep the internal database of installed products consistent. Important features such as <a href="/facts/Rollback_(data_management)/HNtToVYw">rollback</a> and <a href="/facts/Version_control/pxCmFXqK">versioning</a> depend on a consistent internal database for reliable operation. Furthermore, Windows Installer facilitates the <a href="/facts/Principle_of_least_privilege/sqsT4tln">principle of least privilege</a> by performing software installations by proxy for unprivileged users.

Windows Installer open-in-new

Windows Installer