I've been using Sony Vegas Products (currently running Vegas 20) on and off for years and I've never dealt with a glitch or error like this one before. Sometimes when editing some frames will completely go missing or glitch out with a black frame in place of my original video in the video preview. After rendering those same black screens stay in the video which makes them look bad or unprofessional. 

I've tried online tutorials, looking through the forum, and reaching out to support.

I use this everyday and with this issue I've been struggling to make anything for the past week and a half. Please help.