Windows cannot obtain the domain controller name for your computer network. (A socket operation was attempted to an unreachable host. ). Group Policy processing aborted.
In this case, the computer was trying to reboot from updates while a user had the screen locked and programs opened. Once they were logged out, the machine rebooted and the messages stopped.
If this message is logged repeatedly on a computer that is a member of an AD domain, then this usually indicates that the network settings (in particular DNS) of the computer are incorrect.
This event is often accompanied by the event 15 with source "AutoEnrollment".
Make sure that:
1. The DNS server settings of the workstation point to the domain controller(s) that have the DNS service running, and also ensure that they are in the correct order.
2. That the WINS settings are either empty or point to a computer that has WINS running.
3. Check the hosts and lmhosts file to make sure it does not contain incorrect settings.
A reboot or running "gpupdate" usually triggers this error, so you can verify that your changes resolved the problem by doing either.