An ACW file acts as a non-audio project record in older Cakewalk software, holding track layouts, clip positions, edits, markers, and occasional tempo or mix data, while the real recordings remain in separate WAV files that the ACW points to, meaning the file is small and may load with missing/offline media if those referenced files aren’t present or if folder locations have shifted.

For this reason, you usually can’t turn ACW into a sound file immediately: you need to open it in a DAW, relink missing clips, and export the mix, although ".ACW" may also belong to other obscure programs like old Windows accessibility wizards or corporate workspace files, so checking where it came from and what’s in the same folder is the quickest way to identify it—WAVs plus an Audio folder strongly suggest an audio-project file.

What an ACW file essentially does in Cakewalk setups is a project/session container full of metadata rather than sound, acting in legacy Cakewalk environments like a "timeline blueprint" describing which tracks exist, how clips are placed, their start/end points, the edits performed, and project-wide details like tempo, markers, and sometimes basic mix or automation features depending on version.

Crucially, the ACW stores pointers to the real audio files—usually WAVs in the project folder—so it can rebuild the session by pulling those recordings from their locations, which explains why ACWs are small and why projects break when moved: missing WAVs, altered folders, or changed drive paths make the DAW report offline audio since the ACW is basically saying "this take lives here," and that place no longer exists, meaning you should keep the ACW with its audio folders and open it in a compatible DAW to relink clips before exporting a proper MP3/WAV.

An ACW file won’t "play" because it’s not meant to contain audio, holding timeline info—tracks, clip timing, fades, edits, markers, tempo/time data, and sometimes simple automation—while the actual WAV recordings sit in other folders, so Windows media players can’t treat it like MP3/WAV, and even within a DAW you’ll hear nothing if the referenced audio was moved or renamed; solving it means opening the session in a compatible DAW, restoring the Audio folder, relinking missing clips, and then exporting a standard mixdown.

A quick way to figure out what your ACW file actually belongs to is to treat the folder as evidence, starting with where it originated—music/project folders containing WAVs or Audio subfolders strongly suggest a Cakewalk session, while system or enterprise locations point to a non-audio settings file—then checking Right-click → Properties → Opens with, because whatever Windows shows (even incorrectly) can help distinguish between an audio editor and an administrative program.

After that, look at how large the file is—tiny files are often settings/workspace containers, while audio projects stay lightweight but normally appear next to big media folders—and then open it in Notepad to see if readable clues like paths show up, because heavy gibberish suggests binary data that might still contain directory strings; for a more certain answer use tools such as TrID or magic-byte analysis, and finish by opening it in the software you suspect created it to see if it asks for missing audio, signaling a session file.