This has happened twice so I am reporting it now. After a crash I reopened 4.0 and displayed the Home Page. No problem. I then tried to select the layout I had open when the previous crash occurred. Crash.
Last time this happened, I again reopened the program, selected another layout first and it opened fine. Then I could select the layout on which the first crash occurred and it opened just fine. I will try that again. (Hope this makes sense.)