An ACW file primarily serves as a project timeline file for older Cakewalk DAWs, holding track organization, clip timing, edits, markers, and occasional tempo/mix info, while the true audio lives in external WAV files the ACW references, keeping the file small but causing offline media if those files aren’t included or if storage routes have changed.

That’s why you can’t export audio without opening the ACW—you must load it into a DAW, restore missing media if needed, and then bounce or export a mix, though ".ACW" can occasionally come from unrelated systems such as legacy Windows accessibility tools or enterprise workspace settings, making the simplest identification method to look at its origin and folder contents; if WAVs and an Audio folder appear nearby, it’s almost certainly the audio-project form.

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 uses pointers that lead to external WAV files so it can reassemble the project on open, which keeps the file small but causes problems if folders, drive letters, or file locations change; when the DAW can’t find what the ACW points to, clips show as missing, so backups should include the ACW and its audio folders, and producing a standard MP3/WAV means loading the project in a compatible DAW, repairing links, then exporting a mixdown.

An ACW file often "doesn’t play" because it’s simply a session descriptor, functioning in Cakewalk-style workflows as a layout container that holds tracks, clip placements, edits, fades, markers, tempo settings, and sometimes light mix or automation data while the real sound exists separately as WAV files, so double-clicking it gives media players nothing to decode, and even the right DAW may stay silent if those external recordings are missing or relocated; the fix is to open the ACW in a compatible DAW, ensure the Audio folder is present, relink files, and export a proper MP3/WAV.

A quick way to confirm what your ACW file actually is is to use a few targeted checks by examining high-signal indicators: first look at where it came from and what sits next to it—if it’s inside a music/project folder with lots of WAVs or an Audio subfolder, it’s probably a Cakewalk-style audio session, while if it appears in a system or enterprise directory, it may be a settings/workspace file; then check Right-click → Properties → Opens with (or "Choose another app") to see what Windows associates it with, because even an incorrect match can still reveal whether it leans toward an audio tool or an admin utility.

After that, note the size—very small KB values commonly point to workspace/config files, whereas audio sessions remain compact but live next to large audio assets—and then view it in Notepad to spot readable indicators such as workspace, since garbled output suggests binary content that might still leak directory strings; if you need firmer identification, run it through TrID or check magic bytes, and then open it in the expected application to see whether it looks for missing media, a strong sign of a project file referencing external audio.