Final Cut Pro render files: are they safe to delete?

Where it is

What it is

A Final Cut Pro library is a package, by default in your Movies folder, with a name ending in .fcpbundle. Besides your events and projects it holds generated files: render files for effects and titles, and optimized or proxy copies of your media if you asked for them.

Generated files exist to make editing and playback smoother. All of them are made from your original media, so Final Cut Pro can rebuild them at any time.

They grow with every effect you preview and every project you work on, and they are kept after a project is finished. A library can end up several times larger than the footage in it.

How big it gets

Often tens of GB per library, and more on long projects with optimized media.

How to clear it by hand

1. Open Final Cut Pro and select the library in the sidebar.
2. Choose File, then Delete Generated Library Files.
3. Tick Delete Render Files. Choose Unused Only to keep renders that current projects use, or All to remove every render file.
4. Tick Delete Optimized Media or Delete Proxy Media as well if you want that space back and your original media is still available.
5. Click OK. To clean a single event or project, select it and use the matching Delete Generated Files command in the File menu.

What happens afterwards

Final Cut Pro renders again in the background as you work, so playback of effects may be less smooth for a while. If you deleted optimized or proxy media, editing uses the originals, which must be connected and can be heavier to play back.

How Diskzy handles it

Diskzy shows each Final Cut library and its size on the disk map, which tells you which libraries are worth cleaning. The deleting itself is done from Final Cut Pro.

Related guides

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