Form the same lesson learned in the past.
I had more or less the same problem in a 4.09 project, I believe, and of course I did not make a back up. To save the work done I created a blank project and from the host crashing project I moved each of the content files over one at a time until the project would crash. In my case I got lucky and it turned out to be a single malformed image that I replaced from storage.