Unable to export mp4

[helenk31267321]

I'm having an issue exporting mp4 files. When exported, the file shows up as a mp4 with a blank screen and a m4v file. I've attached an image below. Never had this problem before, any help would be appreciated 

[Peru Bob]

Please post screenshots of your media properties, sequence setings, and export settings.

What are the complete computer specs, including hard drives (how many, what kind, what is on each, what capacity, and how full)?

If NVIDIA graphics, make sure to use the latest Studio Driver from NVIDIA (NOT the Game Driver).