I'm using Sony Vegas 13 for over 3 months now, and had nothing to complain, amazing software.

However, in my last project, I started editing a video, spent 3 hours working on it, and when I rendered, I only had the audio in the end product. After, I noticed that suddenly all the video tracks showed pitch black on the preview screen.

I tried closing and reopening. I noticed when I reopened the file, it showed the first seconds of the video preview, only to start going black for the rest of the video. Also, I noticed the video tracks that were images I made on photoshop, showed just fine, meaning it's something related to the Iphone recorded video files only.

What's even stranger, is that in the 3 hours I worked on the editing, everything worked fine, preview, etc.

I also did other projects before using the same techniques and files from the same Iphone.

The videos I'm using were all recorded using an Iphone 6s.

Tried turning off GPU acceleration (I use a GTX 1070) and no solving.
Unchecked the "close media files when not active" option and still nothing.

Please everyone, help me out, I need this video done for the next week, and I can't find a solution.