Error: The selected video does not match the existing video.

I am using VIRB Edit 3.3.1 for video of bike rides

My normal workflow is to create two videos, one with overlay gauges and one with none. I then take both files and do my editing in iMovie on another PC.

I just picked up one to work on and spotted a mistake, so I came back to redo the videos. Now I can't access any of the clips or run the previous projects. It gives a missing clip error, and an option to locate it. If I try to reload it the I get an error "TThe selected video does not match the existing video. Try again?". I can see that it is the correct video.

I did upgrade VIRB before I started, I hope this has not created the problem.

How can I recover my original project.