Recently I have been working in Vegas and have found that certain files have lost information. The capture was clean, the projects have been running fine, but after closing and re-opening certain projects I have found that certain files have large sections of Black with no recognizable video information. Before closing the project, all of the information was seen on the timeline, but after closing and re-opening, information was missing even though the length of the file is still present. Do you have any information as to why this might be happening?

Thank you.