Hello! SwiftUI preview does not work. I tried different versions of Xcode, deleting the "Developer" folders, clearing the "Build" folder from the project in Xcode, reinstalling Command Line Tools and Developer Tools. I think that the error appeared after I cleaned Xcode with CleanMyMacX, before that the preview worked.
-MacBook Pro (15-inch, Mid 2012) -macOS Catalina 10.15.7 -Xcode 12.3
Thanks for the feedback!