Could not insert new outlet connection [duplicate]

I got the same problem as you today… I think this is a bug of Xcode, below is the way to fix the issue: Close the project you are working on with. Delete your project’s【DerivedData】folder. (This folder may inside your project’s folder, or inside ~/Library/Developer/Xcode/DerivedData/(your project)/ ) or somewhere else that was setup by you. … Read more

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