I'm editing some 1080 30p .mov video from a new iphone in VP 13 Win 10 64. About half-way thru editing the project, Vegas hung - became non-responsive - I had to force stop the program in the Task Manager. Since then the video previews for my clips started dropping out and now are completely gone (audio previews fine). I don't get any video previews in the trimmer or preview window (I can see thumbnails on my timeline and in the explorer window). I installed Quicktime 7.7.9 before starting the project and reinstalled it. I've tried restarting Vegas and my computer but no luck. Ideas?