Why can't I import media into FCP X?

Hello.

Every time I try to import media files into FCP X, all I get is a green screen in playback and no sound (see picture). I can't get it to play on Quicktime either. They're MPEG-4 files from a Sony EX1 camera.

Maybe a codec issue?

You cannot import files from almost any camera like this.

First you save the card´s content or connect the camera.
Then you choose "Import from Camera" and either point at the camera´s card or the directory where you saved the card´s content.
Now you get a Import dialogue that is self-explanatory and the same for XDCam, P2 or XFcam.
Press "Import All....", now you can close this dialogue and instantly edit away, while FCPX imports the media in the background into its event under "Original Media".

For P2 you don´t need anything. For XDcam and Canon´s XF you need their plugins from their sites.

It is never a good idea to import the pure mp4 or mxf files fromcameras, because they will miss the audio, metadata or simply won´t work.