Same here with a lot of performance issues on previews Debug console for previews also have stopped to work with Xcode 12 (worked fine with Xcode 11) I develop on a MacBook Pro mi-2014 I’ve posted many questions/issues about Xcode 12 SwiftUI previews but no answer. I wonder if I need a paid account to get some answer through this forum So I’ve stopped to develop since I fed up with this release and to be ignored Good luck