Hey, I ran into the exact same problem and ended up building a small Mac app to solve it.
It’s called FCP Tagger — you export your timeline as XML from Final Cut Pro, open the app, pick a Finder color, and it automatically tags every media file you’re using. Then just sort by color in Finder: tagged = in use, no tag = safe to delete.
Supports .fcpxmld and .fcpxml, works offline, available in English and Spanish.
https://danzelot.gumroad.com/l/fcptagger
Hope it helps!
danzelot.gumroad.com
FCP Tagger
You know the feeling. You finish a project, look at your hard drive, and have no idea which files you actually used — and which ones are just taking up space. Deleting the wrong file is not an option. So … Continue reading