Transcode Media for Efficiency in Final Cut Pro
To improve performance and stability, it often helps to transcode the media in Final Cut Pro. The transcoding process creates a new version of your media encoded with ProRes, a codec designed to guarantee higher responsiveness during editing operations.
Right-click on a clip to display its contextual menu
Select "Transcode Media…"
In the Transcode Media dialog, enable "Create optimized media" & click OK
When the "Create optimized media" option isn't available, it means the clip is already encoded in ProRes or that it had already been transcoded on a previous occasion.
Transcoding can be done on individual clips in the Browser or on all media in an Event.
Create optimized and proxy files in Final Cut Pro