Xcode - Error launching WatchKit Extension
The workflow seems to be different depending on your usecase:
- WatchOS app with iPhone app
- Standalone WatchOS app
For usecase 1, I had to trust myself as a developer in the iPhone Settings -> General -> Device Management. Note, you need to try and run the app on your devices before the menu option is available on the iPhone.
For usecase 2, I had to trust myself as a developer at the prompt that was shown when I opened the app on the watch for the first time.
My advice would be to try to get usecase 1 working first, before trying usecase 2. Note, if you have a free developer account you will need to uninstall the usecase 1 app from the iPhone and from the watch before you can install usecase 2, as the free account only supports one app at a time.
I wasted time by starting with usecase 2 and could not get it to work for some reason. After I gave up and did usecase 1, then subsequently tried my usecase 2 app again without changing any XCode settings, it just seemed to work for some unknown reason.
I'm using XCode 11.4, iOS 13.4 and WatchOS 6.2 on iPhone 7 Plus and Apple Watch 2 42mm
This setting should be set to Trust(your Apple id) in Settings -> General -> Device Management ->
I resolved this by opening the app on the Apple Watch for the first time, then selecting "Trust developer" on the prompt that appeared.