This project is invalid or corrupt and cannot be opened...

The same thing has happened to me 2x in 2 weeks now.  I spent several days re-creating the work.  I saved the story file 2x a day so that I would have a clean backup.

Now it appears that my working file and each of the backups are giving me the same "This project is invalid or corrupt and cannot be opened. It may have been created in an earlier version of Storyline."

I don't really require an expression of sympathy, a heartfelt "Yeah, that's too bad!"  as much as a root cause analysis of why this keeps happening and a way to prevent it from happening again.

It may be that I haven't been updating the program every time I get a message that updates are available:  I would rather not write tickets to IT every other day.

I followed the tips from Nicole by backing up the files:  for those in a similar situation, it only seems to work if I back the project up to Team Slides rather than my local laptop.  The problem with that is that I'm not sure if I can work from home if I do that.