Half of film comes out black during export
I'm hoping someone here can help with an issue II'm experiencing when exporting my film.
The export seems to work fine, but when I open the file only the the first half of the film shows, and the second half is just showing a black screen (but the audio is exported).
Does anyone know what the issue could be? I've tried exporting as .h264 and also Prores422, and the issue is the same on both.
I can see and edit the film fine in the timeline, so can't identify what is causing an issue when I export.
Any help most appreciated.
thanks
MacBook Pro (Retina, Mid 2012), OS X Mavericks (10.9.2)