Скопировать Пользователей с Сервера 2 012 Основ перед обновлением R2?

I haven't done an installation of Windows Server 2012 R2 Essentials into an existing Windows Server 2012 AD domain, but I just did an install into a Windows Server 2003 AD domain last week and it worked fine. I was able to join the existing domain, promote my W2K12 R2 Essentials machine to a DC, and then retire the existing Windows Server 2003 DC. It worked out just fine.

Were I in your situation I'd:

• Join a temporary virtual machine to the domain (running W2K12 Standard in evaluation mode if nothing else)

• Demote the current W2K12 Essentials DC back to being a member server

• Move any files off the "C:" volume of the W2K12 Essentials machine you need to save

• Reformat the "C:" volume and install the new W2K12 R2 Essentials software as a replica domain controller on that machine

• Migrate files back to the new W2K12 R2 Essentials machine

• Complete the installation process ending with demotion and removal of the temporary VM

I'd mock this up with VMs before I actually did it, just to be sure it all worked smoothly in real life. It looks like a solid plan to me.

I wouldn't do any kind of "backup / restore" of AD, or any type of AD migration. Using AD's existing replication functionality is the way to handle this problem.