I'm also seeing this issue, a week later. How about providing support in the latest release of Xcode for the latest release of the various OSes? Crazy, right? Now if Apple could just make Apple Watch coding work reliably, with no witchcraft or rubber chickens, repeatably...

I am so with you... and unfortunately 20 reboots later, 'reboot everything' still doesn't work for me. To make matters worse the few times I've gotten it to work over the past few years, it then STOPS working again pretty quickly.