What is the NWC file format?
.nwc files store musical scores, not audio tracks - the format is a music-notation (sheet-music) container, not a recorded-audio format. Score data includes staves, clefs, time and key signatures, notes, lyrics, dynamics and playback settings in a compact proprietary binary structure. Audio output is synthesized at playback time via MIDI rather than stored as waveforms.
.nwc files are primarily used by NoteWorthy Composer, a Windows application that can edit, play back and print .nwc files, giving users a capable environment for advanced score editing. The full version of Composer is paid software, but a free separate application - NoteWorthy Composer Viewer - is also available. The free viewer allows users to open and play back .nwc files but not edit them.
Every .nwc file begins with a recognizable ASCII identifier ([NoteWorthy ArtWare] or [NoteWorthyComposer]) at byte offset 0, followed by binary score data. The format has two generations: NWC 1.x and NWC 2.x; a v2 file cannot be opened in v1 of the program. Scores can be exported as the plain-text .nwctxt for third-party interchange, or converted to a MIDI file for use in other music software.
Security & safety
RISK: LOWNWC files are music-notation data and are safe to open in NoteWorthy Composer or its free Viewer. They are not executable. Download the NoteWorthy Composer/Viewer only from the official noteworthycomposer.com site to avoid bundled-installer mirror sites. The main confusion risk is the name clash with Autodesk Navisworks .nwc cache files - make sure you have the right kind of .nwc before troubleshooting.
Format details
in a nutshellPrograms that open NWC files
Windows3 apps
NoteWorthy Composer
Paid Open the .nwc to view, edit, play and print the full score; this is the authoring program (free trial available). 
Noteworthy Composer Viewer
Free Free official viewer - open the .nwc to view, play and print the score (read-only, no editing).
MuseScore (via MusicXML)
Open-source Cannot open .nwc directly; export the score to MusicXML in NoteWorthy first, then open the .musicxml in MuseScore. 
macOS1 app
NoteWorthy Composer (via CrossOver/Wine)
Paid No native Mac build; run the Windows NoteWorthy Composer/Viewer under CrossOver or Wine to open .nwc. 
Linux1 app
NoteWorthy Composer (via Wine)
Paid No native Linux build; run the Windows program/Viewer under Wine to open and print .nwc scores. Technical details
deep spec| Developer | NoteWorthy Software, Inc. |
| Format type | Proprietary binary music-notation score |
| File encoding | Binary with ASCII text header |
| Magic bytes | `[NoteWorthy ArtWare]` or `[NoteWorthyComposer]` at byte offset 0 |
| Byte order | Little-endian |
| Compression | None - compact binary score, not a compressed archive |
| Encryption / protection | None; a read-only save flag exists but provides no strong protection |
| Typical file size | 5 KB - 200 KB, depending on stave count and measure length |
| Format versions | NWC 1.x and NWC 2.x; v2 files are not backward-compatible with v1 |
| Stored content | Staves, clefs, time/key signatures, notes, chords, lyrics, dynamics, tempo and playback settings |
| Audio output method | MIDI synthesis at playback time; no embedded audio data |
| Primary platform | Windows; also usable on Linux and macOS via Wine or CrossOver |
| Related text format | `.nwctxt` - plain-text export of the same score, used for third-party interchange |
| Read-only variant | `.nwd` - a locked NoteWorthy Viewer file derived from an `.nwc` score |
| MIME type | `application/octet-stream` (no dedicated registered MIME type) |
| Released | 1994 (NoteWorthy Composer for Windows) |
| Latest version | NoteWorthy Composer 2.x file format (NWC 2) |
| Specification | noteworthycomposer.com |
NWC conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about NWC files.
