Ok, I have fully wiped my phone - everything! (3x, as usually recommended)
I reinstalled SS 5.6. Reinstalled all my apps, etc.
Now, I still get the "Sorry! Process system is not responding" error. I usually choose "wait" and things seem fine. How can I prevent from getting this?
(The only thing I noticed is that I'm not sure I had it before installing the latest Google street view. But then again, before when I had the problem, it was doing this before I installed that. So I'm not sure)