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I want to reinstall my 2008 R2 server from scratch, due to multiple Active Dir issues. I have only 1 server running AD and a spare machine to use if necessary.

Is there a way to save just the user accounts and the domain SID, so that I can start with a clean server that uses the same name as before?

I can reassign file security, but I do not want to have to rejoin all the users to a new domain. Also all users are mapped to folders on the server.

What I hope to do is a clean install of the server without having to mess with the users machines.

can someone please tell me the procedure to accomplish this?

any help appreciated!

Thanks guys, but I could be here all day telling you every error I am getting. can we please keep this to the question of how to do a reinstall and keep the same SID?

I just want to start over without having to rejoin all the clients to a new domain.

Is there such a tool that can backup the Server SID and the AD domain name so that I could restore them, without restoring any other data?

I might not be using the correct terminology here, but hopefully you understand what I am asking. Thanks

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You can't reinstall and keep the same domain SID. Your only option to retain the domain SID is to promote another domain controller and transfer roles (as @SpacemanSpiff suggests). Why don't you try telling us the error you're getting instead of telling how you wish you could solve the problem? There's virtually nothing that you can do to an Active Directory that can't be fixed after-the-fact, so let us give you a try. Some specific error messages and the scenario would be helpful. – Evan Anderson Feb 7 '11 at 21:13
I am going to promote a second DC. backup is running right now. be back tomorrow to post some of the error messages. Thanks for the help. – user69835 Feb 7 '11 at 22:38

Install a new 2008 server... join it to the domain, promote it to being a domain controller, transfer all FSMO roles to it. Then demote the old one, remove it from the domain, and reinstall as you please.

Keep in mind you may be using that first server for other things, DNS, DHCP, etc.

The second server should automatically bring up DNS for you and move all the records over. You really should always have at the bare minimum TWO domain controllers.

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This was my original plan, I have actually done this, but all the AD problems just get transferred to the new server. The problems were caused from installing SQL and Exchange 2010 on a DC. Neither one wanted to remove cleanly, and now I have a mess. – Chris Feb 7 '11 at 19:34
@Chris, how exactly is your AD messed up? You might be able to migrate the objects (or something similar). SQL doesn't mess with AD. Exchange 2010 does, but the schema extensions don't usually cause problems (schema changes are not reversible, as was explicitly stated during installation). – Chris S Feb 7 '11 at 19:36
Well, I am getting all kinds of errors in the logs. the Hypervisor role refuses to install, multiple unresolved accounts from group policy, No mapping between account names and security IDs was done. – Chris Feb 7 '11 at 19:40
It is because of Exchange 2010 that I am doing this. – Chris Feb 7 '11 at 19:43
Are you sure you're not just running into a clash of roles? Can a Domain Controller ALSO be a hypervisor? I think not most likely. Let's have some more details here. The schema extensions should not be a problem. – SpacemanSpiff Feb 7 '11 at 19:56
  1. Install Windows on the 2nd box, install AD (et al)
  2. Migrate FSMO roles to 2nd box.
  3. "Uninstall" AD on the server. Un-Join from domain. Reinstall Windows.
  4. See #1, #2, and #3, but on the opposite box.

Sprinkle "backup" into the mix generously.

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