I finished a project using iPhone footage with no problems at all. I renamed the original .MOV videos to .WMV because usually there is preview lag when i use the regular .MOV files. When I attempted to render the videos, the preview was black, and when the project was done rendering, the first couple of seconds were fine, but then the rest of the project was black, but I can still hear the audio. I tried opening another project and copying and pasting, but the same thing happened when I rendered. I set the GPU acceleration of video processing off, and it still didn't work. Please help I've been trying to look for a solution for the past 3 hours.
It is Vegas Pro 14 64 Bit, Windows 10 OS. I have a i5-4690k 4.5 ghz , and a gtx 1060 3gb GPU.