MUI meaning in Computing ?

Multilingual User Interface (MUI) is the name of a Microsoft technology for Microsoft Windows, Microsoft Office and other applications that allows for the installation of multiple interface languages on a single system. On a system with MUI, each user would be able to select their own preferred display language. MUI technology was introduced with Windows 2000 and has been used in every release since (up to Windows 10). The MUI technology was covered by an international patent titled "Multilingual User Interface for an Operating System". The inventors are Bjorn C. Rettig, Edward S. Miller, Gregory Wilson, and Shan Xu.

Functionally, MUI packs for a certain product perform the same task as localized versions of those product, but with some key technical differences. While both localized versions of software and MUI versions display menus and dialogs in the targeted language, only localized versions have translated file and folder names. A localized version of Windows translates the base operating system, as well as all included programs, including file and folder names, objects names, strings in registry, and any other internal strings used by Windows into a particular language. Localized versions of Windows support upgrading from a previous localized version and user interface resources are completely localized, which is not the case for MUI versions of a product. MUI versions of a product do not contain translated administrative functions such as registry entries and items in Microsoft Management Console. The advantage of using MUIs over localized versions is each user on a computer could use a different language MUI without requiring different versions of software installed and dealing with the conflicts that could arise as a result. For example, using MUI technology, any version of Windows can host Windows applications in any other language.