I had something similar happen a long time where a .veg file wouldn't open because one of the video events in the project was - as it turned out - corrupt. It was a long time ago and the Windows installation was probably 8.1 and the Vegas Pro verrsion was either 11 or 12. The problem was solved at the time by putting Windows into Safe Mode which enabled the problematic .veg file to be opened. It was then a case of tracking down and deleting the corrupt video event (it's thumbnail appeared in Vegas's Explorer window as an icon rather than with a representative image of its content) and saving the project with a new name.

After reverting Windows back to its normal state, the newly named .veg project opened up without a problem and normal editing resumed. Where or not this would work with Windows 10 or 11 is another question, and I can't recall ever having to use Windows 10 or 11 in Safe Mode.

Another approach might be to delete/remove the possibly corrupt event from the project folder assuming that you know which is the possible corrupt event.

@Dexcon, from your thought... I wonder if we can do another 'much-easier-alternate' approach that was caused by corrupt video events inside the project: try to 'disconnect' the source media files from the project? So which means, make the situation where VEGAS Pro can't find the source media, let it missing temporarily by renaming the folder or move the folder somewhere else. Once successfully opened, just resave the project with different file name.

Can't remember if I ever did this once..., but this can be one alternate way to try.

@set  ... yes, you are completely right. That was the meaning of the last sentence in my comment ("Another approach might be ...") but I was remiss in not completing the process as you've now detailed. That wasn't possible for me all those years ago because I didn't know which event was corrupt, but the OP may have an idea about the problematic event based on recalling the event that was being worked on at the time of the 'crash'.