MUSX files were chiefly used in legal sector. Such files typically contained audio transcripts created during, for example, court proceedings or interrogations. The tool that supported MUSX files — Min-U-Script Xpress — was available for free.

License for the current version of Min-U-Script Express Pro can be purchased for ca. four-hundred dollars. The free version of Xpress was discontinued, and MUSX files are no longer used. However, MUSX files may be opened with Express and exported to the universal PDF format.