Xcode 12 GM: Main.storyboard doesn't load

I Installed the Xcode 12 GM today & I was able to run a debug build on-device & upload a distribution build for TestFlight. However, the Main.storyboard file refuses to load. Xcode either freezes or the activity indicator spins endlessly. This wasn't a problem on Xcode 11. Is anyone else experiencing this issue?
I was able to "regain" access to my Main.storyboard after removing some auto layout constraints that produced runtime warnings. I edited the source code of the storyboard to remove the constraints and, voila, the storyboard loaded properly.
Where did you remove the auto layout constraints ? Wasn't it in the mainStoryboard ?

When you have problem with storyboard, it may be a solution to open as XML and try to find is something is wrong (by comparing the same file opened with Xcode 11 for instance).
I am seeing the same problem. How did you identify the constraints with runtime warnings if the storyboard doesn’t load? Go back to Xcode 11 and remove them there?
Xcode 12 GM: Main.storyboard doesn't load
 
 
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