Something similar I wrote a little bit earlier, but it was in another context.
So I have many projects that has many CPR files. Some of them has included all audio files from Audio folder, some of them has only few. Now we don’t have a control over which files are used by all project files and which are not used by any.
Of course we can backup project and specify new path and it will copy only those audio files that are used by project. By one project file, not many. We cannot specify Project1-MIX1 and Project1-MIX2 to copy to new place with all audio pieces that are used by both project files. We can copy (backup) each one separately and then - which is very annoying - go to explorer, open two windows, compare both project folders, delete duplicates and concatenate both projects if they are using the same audio files.
Sometimes this happens many times a day. Just working quickly and worrying about space not only on working disk, but also about all backup drives.
So the Feature Request would sound this way - In a Pool window if we click physically remove file from disk (after we do “Remove Unused Media” and/or “Empty Trash”), Cubase should check all CPR files in the same project folder. If it can do this on one CPR file that is opened, it also can open many files (not loading anything, just open file to read track info) and restrict deletion of audio files if any used in other CPR files.