Windows 10 Group Policy Client Service

I've updated to Windows 10 and I can login to my PC okay (I'm the administrator), but other family members get the following message 'Windows couldn't connect to the Group Policy Client Service. Consult your system administrator'.  If I'm logged on, I can change users and it's okay, but otherwise no-one can use our PC. I've had a look at the registry, but it won't let me change any of the settings.

Any ideas? Thanks.