Free Up Final Cut Space - Render, Optimized, Proxy

Deleting render files obviously is not supposed to delete your media.

Render files are created by the software, and can be recreated later when - and if - necessary (which may be never!).

You probably do not need to render at all.

The usual recommendation is to turn background render OFF in Preferences->Playback.

This alone will considerably reduce the disk usage by not creating unnecessary files.

Also, do not create Optimized or Proxy media unless there is a good reason for it (like if your mac has trouble playing back, you may need to work in proxy).

Missing files are not caused by deletion of render files, but by removing of the actual media...

One deletes render files from inside FCP: select the library, and go to File->Delete Generated Library Files...

and check "All Render Files" - that is also where you can delete optimized and proxy media.

Is that what you were doing when you were trying to delete render files?

Or where you messing with the library bundle in the Finder?

Don't mess with files inside the library bundle unless you're sure you know what you are doing. You can inadvertently corrupt the library and break it. Follow Luis' instructions and remove render, optimized and proxy files from within FCP.

And to reiterate: if you delete render files, it is expected that your files are all there as they were.

Depending on the settings, though, you may be able to recover some or sometimes a lot of space.