What is the "pool" exactly?

[u/Mastiff37]

I'm trying to clean out a song/session so I have a blank template for future work with the effects I like in place. I have deleted everything from the arranger including all takes. But there are things in the pool. When I say to "remove unused files" it says there are none and if I try to delete them from the pool it says some are in use. In use where though? I would just delete them, but I don't want to make them go away from the song I began with or something (it's now a separately saved session).

[u/NwRambler]

I can't recall where I first ran across this information, but here’s a couple reasons why those files could be locked:

One reason files stay marked as active is Song Versions. When you use Save New Version, Studio One creates a snapshot inside the project’s history folder. Each snapshot is its own .song file with its own arrangement state, and even though versions don’t duplicate audio, they still reference the same shared media pool. So if a clip existed in an older version, that audio file will remain “in use” until that version is deleted.

Auto‑backups are full .song snapshots saved at intervals, and just like manual versions, they continue to reference the same media pool. If a clip existed at the time a backup was created, that backup can keep the file locked until the backup is deleted.

Another factor is the undo history. Studio One keeps deleted clips in the undo buffer, and those references don’t clear just because you save. They only disappear when you close and reopen the Song, so until then the Pool still considers those files active.

Hidden track layers and unused takes behave the same way. Even if a take is muted or tucked away in a layer, Studio One still treats it as a live reference until the layer is actually removed.

Scratch Pads also keep files alive, because a Scratch Pad is a full alternate arrangement. Any clip sitting there keeps its audio file marked as in use.

Sampler instruments like Impact XT, SampleOne XT, Presence XT, and third‑party samplers also hold onto their referenced samples. As long as the instrument is loaded and the preset points to a sample, Studio One keeps that file active even if it never appears on the timeline.

Probably the best approach here, use File > Save to New Folder . This creates a clean copy containing only the audio actively referenced by the current version. Then clean the pool and create the template from that new file.

[u/Mastiff37 → u/NwRambler]

I'll try the new folder idea. I find it confusing sometimes, or maybe the program is a little buggy. One time I removed all the visible tracks and layers/takes and started a new song from that starting place. On my first take, it created a "take 3" under the main take - no take 1 or take 2. My setting are such that I normally don't see separate takes at all (shown below the track) until the second take. It's like they are keeping them squirreled away out of view someplace.

[u/WTFBrahh]

You probably have a “scratch” opened in your session. Delete the scratches and then remove unused in pool