MuseScore is a WYSIWYG (What You See Is What You Get) music notation program licensed under the GNU GPL. Musescore versions 0.9.5 or later save files as .msxc as an uncompressed file allowing for easier text-editor manual, on the fly editing. Earlier versions of MuseScore saved files as .MSC, experiencing conflicts within the Windows environment.
MuseScore is a cross-platform application with packages available for Windows, Mac and Linux and has been (either fully or partially) translated in 43 different languages. It incorporates a sequencer and software synthesizer and is capable of importing and exporting MusicXML and MIDI files.