After putting it off because I didnt want to disturb my current stable installation of canvas 4, I tried installing the canvas 5 demo on my machine today (powerbook 2009, el capitan).
Software refused to start up first time, quitting without getting to the splash screen.
thankfully 4 still works.
Here is the link to the old thread where I complained about this last time:
I remember the issue, we just were never able to reproduce it inhouse. Doesn't mean it doesn't exist. Maybe we are missing a step or two, even if it is intermittent sometimes every step is important. Usually intermitten problems are linked to memory corruption of some sort, or in this case screen redraw. I will take a look at the old message and see if I can try it again. I will also look at our database and see if something was done to reduce it or even stop it from happening.