I had the same thing happen to me about the white screen. I am not an advanced – my project five minutes, very simple. I have moved from PP CS6 to CC. I was freaked [never happened to me in CS6] glad to see that this does happen to others. I now think this happened to me, because – just in case it might be the reason for someone else…… My issues [I believe] was the photographs I was using, and format, when I changed all the photos to 72 dpi, and made them png the white did not happen. Could be fluke or this was the reason….I was able to key frame, no problem. I also turned off Display Color Management [requires GPU acceleration] I had turned it on the day before, I had a problem. . The next day white issues…..One of my thoughts that might have been the reason? I will turn it back on…see if it happens again. My husband is in IT, he checked my graphics card in my computer and said good card should handle. In my research, it was also recommended besides 72 dpi, 3840 x 2160….some were a little bigger…maybe it was change to 72 dpi….So for now all is well.
I have saved the other information recommended, just in case, happens again…photos are not on the timeline…I know this is long, but I wanted to contribute just in case………