I installed Xcode 8.1 and the storyboard shows only blue lines, for all UI elements. If someone has figured it out let me know. I am unable to revert it to even Xcode 8.0.>
This has happened to me on several occasions. For me it almost always occurred after dragging a UILabel
from a UITableViewCell
into a different view.
I was able to fix the problem by deleting the view controller in the storyboard that I did the dragging to/from, closing the app, and reopening the project.