I just upgraded to Lightroom CC from 5.7 and all my photos look like this now:
The problem is in develop mode only. They look fine in the grid and loupe views and when I export them as well. I can also edit them normally, although it's hard to see what I'm doing. Also, all my photos are taking a lot longer to load now as well. What gives? I've restarted my computer but it didn't help. Thanks!