I think this is what you're referring to: https://developer.apple.com/programs/video-partner/resources/

For me I had to delete ~/Library/Preferences/com.apple.dt.Xcode.plist and it started working. Alternatively, check Preferences -> Locations -> Derived Data and Archives and see if a non-valid path is supplied, upon further inspection I think that was my issue (migrated my Xcode preferences from a different computer).

For what it's worth, I am able to get SharePlay to work with a AVPlayer based system (custom controls). The logic is that after we receive the activity, we create our player and during the process of configuring the player, if there is a group session we attach it to the playbackCoordinator. Hope that helps.     if #available(iOS 15, *) {       if let session = CoordinationManager.shared.groupSession {         player.playbackCoordinator.coordinateWithSession(session)       }     }