A - Checkerboard Image At Export?
Using a plugin and finding that the media is being lost after exporting?
This will occur when the plugins that are being used are not stored on the same hard drive as the project they are being used in.
When exporting a project that is stored on an external drive, Final Cut will remove all media files that are not stored on the same drive as the project.
Make sure that all files associated with Final Cut are stored on the same hard drive as the project that they are being used in to prevent this issue from occurring.