In the event an app on your Apple Watch stops responding, you can force quit the app instead of restarting your entire device. I've had to do this a number of times since iOS 10 andwere released.
The next time you find yourself staring at a watch app that won't load, or is behaving oddly, try this:
- Press and hold the side button (the button just below the Digital Crown) until the shutdown screen appears.
- Let go of the side button, then press and hold the Digital Crown.
After a few seconds, a brief animation will return you home screen of your watch. The end result is the app being closed. This process is specific to WatchOS 3. Earlier versions of WatchOS required you to hold in the side button until the shutdown screen appears, then release and press it again. With WatchOS 3, the side button now activates the new Emergency SOS mode.
Editors' note: This post was originally published on April 27 2016, and has been updated to clarify the new process with the release of WatchOS 3.