On Xcode 9, all my storyboards seem to be displaying in blue outlines only. Doesn't seem to be a new feature....Anyone has the same issue?
After a week of trying all the suggestions in the internet I found that Xcode 9 required some libraries in macOS High Sierra.
So install them and then it will work:
https://www.apple.com/lae/macos/high-sierra/
Hopefully it will help someone
I has this issue in two different storyboards, where I can see an error on the top which said:
"An internal error occurred..."
In one of them I could solve the issue removing Derived Data following this steps on Xcode:
Preferences > Locations > Derived Data > click the arrow to open in Finder > Delete it
In the other one I wasn't able to solve it so I'm using Xcode 8 for that Storyboard (You can open both Xcode 8 and Xcode9b2 and code with them at the same time)
This recommendation might helpful for others who are not able to solve this issue.
This issue could occur If Xcode debugging tools are not installed properly, While installing Xcode 9 from Mac OS 10.12.x. What I would recommend is you go to the below url, and install the additional tools(additional tools, comman line tools...) compatible with your OS version(v10.12 in this case).
i fixed this issue by Hiding Rectangles Bounds
goto Editor -> Canvas -> uncheck Show bounds Rectangles
NOTE: check/uncheck twice if not done on first try
I had the exact same issue after upgrading to macOS High Sierra. Re-installing Xcode + command line tools did not help.
I changed this configuration in Xcode and it made the problem disappear: "Preferences" > "General" > "Locked Files" > "automatically unlock files".
For me, I had both Xcode 8 and Xcode 9 open on same computer. Closing Xcode 8 and reopening Xcode 9 solved the problem.
来源：https://stackoverflow.com/questions/44532110/xcode-9-storyboards-are-not-displaying-properly