An ACW file is essentially an arrangement file for older Cakewalk systems, containing timeline details, track names, clip positions, edits, markers, and occasionally tempo or mix parameters, while the real audio remains in separate WAV files the ACW only references, making the file small but vulnerable to missing/offline clips when the accompanying audio isn’t included or when path layouts no longer match.

Because of this, you cannot make a playable file from ACW directly: you have to open it in a supported DAW, reconnect any missing sources, and export a mixdown, but since ".ACW" can also be used by other niche software—including older Windows accessibility wizards or admin workspace utilities—the quickest way to know what it is comes from context, and seeing WAVs plus an Audio directory usually confirms it’s the audio-project variant.

What an ACW file actually represents in common audio use is a session container full of instructions—not audio—serving in older Cakewalk workflows as a "timeline layout" that captures track lists, clip placements, start/end times, edits like splits and fades, along with project-level info such as tempo, markers, and sometimes basic mix or automation depending on the Cakewalk version.

Crucially, the ACW holds path links to the WAV recordings in the project, allowing the session to rebuild itself by reading those files, which is why the ACW remains small and why moving projects can break things—any missing WAVs or changed directory paths leave the DAW unable to locate audio, so the clips go offline; therefore, always copy the ACW with its audio folders and reopen it in a supporting DAW to relink items before exporting MP3/WAV.

An ACW file doesn’t "play" because it’s a metadata container, not audio, storing clip placements, tracks, edits, fades, markers, tempo settings, and basic mix data while pointing to external WAV files, so double-clicking gives media players nothing usable, and even a DAW may show silence if the WAVs no longer match the original paths; the remedy is to load it in a supported DAW, make sure the Audio folder is present, relink missing media, and export a normal MP3/WAV.

A quick way to identify what your ACW file is involves checking a few strong clues: look first at its surrounding folder—WAVs or an Audio directory usually point to a Cakewalk-type project, while system or enterprise folders suggest a settings/workspace file—and then use Right-click → Properties → Opens with to see Windows’ current association, which can still offer insight into whether the file belongs to audio software or some administrative tool.

After that, review its size—very small KB files tend to be configuration/workspace types, while audio projects remain modest but are usually surrounded by big WAVs—and then inspect it in a text editor to look for recognizable words such as audio, as unreadable characters imply a binary file that might still reveal folder strings; for clearer identification try TrID or magic-byte checks, and ultimately test it with the probable parent app since prompts for missing media almost always confirm a project/session file.