I've seen multiple posts on this but they all point to one of the following solutions:
- Make sure your Intel HD graphics driver is updated to 18.104.22.16886
- Rename the video file from MP4 to an MPG
- Change the project settings from GPU acceleration to Software only
I've tried all of these and closed, re-opened, restarted the computer etc. and still get nothing but a green block in the video preview screen. Hoping someone else has had as much trouble and found a magical 4th solution.