iTunes crashed whilst adding .mp4 and now I can't add that .mp4

Hi,

I was adding a video to movies and when I changed the genre the spinning wheel was on for 5-10 minutes, so I force quit iTunes. When I reopened iTunes the video had disappeared and now it will not let me add it again. I have tried restarting iTunes, restarting my Macbook and deleting and adding the file again, but I still cannot add this video to the library. It is not hidden in home videos as when I search the iTunes library it does not show up.

Any help would be much appreciated.