watchOS beta Software Installation Guide
Beta versions of watchOS software are available to develop apps that take advantage of the latest features of watchOS and to test existing apps for compatibility.
Beta software is intended only for installation on development devices registered with your Apple Developer Program membership. Make sure to back up your devices before installing beta software. Attempting to install this version of watchOS in an unauthorized manner could put your device in an unusable state and necessitate an out of warranty repair.
NOTE: Registered development devices will be able to upgrade to future beta releases and the final watchOS software.
watchOS 3 beta supports iPhone 5, or later running iOS 10 beta.
Installing watchOS beta Software on Your Device
To report any bugs, use the Apple Bug Reporter on the Apple Developer website. Additionally, you may find information in the watchOS beta area of the Apple Developer Forums.
Apple Watch displays a red "!" icon.
You should force restart your Apple Watch if it's displaying a red "!" icon. To force restart your Apple Watch, press and hold both the side button and Digital Crown for at least 10 seconds, then release both buttons when you see the Apple logo.
If force restarting your Apple Watch doesn't resolve the issue, contact Apple for service.
Contacting Apple Support
If your Apple Watch continues to display the red "!" icon, restarts into recovery mode, or exhibits other issues that require it to be restored with the current version of watchOS, you need to send it in to Apple Support. Apple Authorized Service Providers and Apple retail stores cannot perform this service. Visit Apple Support and follow these steps:
Once your device is received by Apple Support, it may take up to 3 business days to be serviced. You will get back the same device you sent in. This service is currently available in Australia, Canada, France, Germany, Italy, Japan, Switzerland, UK, and US.