Symptoms
When a newly installed Windows 10 device boots up for the first time, in the initial setup wizard, you will choose the language and region setting, accept the license agreement, and then choose Next. Sometimes, after that, Windows reboots by itself automatically. After the reboot, Windows starts up again and goes back to language and region setting wizard page. You can still go along with the wizard to complete the initial setup.
Cause
The reboot and return to the language and region setting is because the CloudExpericenceHost appx package fails to be registered during setup, due to a timing issue between Explorer and the AppxDeployment service.
Resolution
Set the language and region again, and continue with setup. It should work after the reboot.
More Information
Microsoft is aware of this issue with Windows 10.