VS x10 time line corruption

[MikesMovies]

Hi guys

I’ve just had the biggest *** up with VS X10 ever.

I made a 4 min video, output to mp4 as normal but discovered a small error in the narration.
Loaded up the timeline again only to find it horrendously corrupted.
Clips had become merged, edits were out of place, music was no longer fitted within the video track limits.
I have never seen such a mess.
Is there any guidance on what caused this and how to fix please?