MUI files are essentially used in Microsoft Windows 2000 and XP operating systems. These files are related to Multilingual support of the operating system. MUI files help the operating system provide its service in many foreign languages, and MUI files are the system files that have the data to enable the operating system for the purpose.
Other programs that use MUI extension files
GLUT:
Glut is a program used by developers and is a utility for writing OpenGL programs. It is a program designed to create small and medium OpenGL applications. GLUT uses files that have an MUI extension too.
Amiga:
Amiga is a program published by SASG which also uses files with the extension MUI. MUI in the context of Amiga stands for Magical User Interface. As the name implies, MUI provides a smooth graphic user interface environment for developers using Amiga.
How to Open MUI Files
All the three types of MUI file extension are system generated and may require an editor only to correct any faults within these files. In the event of any of these files getting corrupt, the respective program that depends on it would stop functioning
Under such situations, you would need a program editor for these 3 types of MUI files.
How to repair corrupt MUI files
FileCure is a great tool that you can use to open not just MUI files but also files of almost all extensions, known and unknown. FileCure opens and scans these files, and looks for the best available opener for the file. In the absence of an apt program, FileCure itself enables opening of the file and helps you fix it.