I had the same issue. Technically, my project was structured like this: The iOS app built fine, but I was having an issue with the watchOS preview. The main issue was that, during the preview, Xcode tended to build the whole project [Main Project - not just My Watch App] using the watchOS destination. I came up with a restructuring solution that worked. Use a workspace and move your common module one level above, like this: In this case, Xcode only tends to build “My Framework Kit Project” with watch destination which solved the issue