Hi there,
I had to depromote an old DC today, it was running Server 2003 and the hardware was failing. Please don't ask why this had to wait until now.
All FSMOs had already been moved to the new one (Server 2008 R2) some time ago, but I re-checked this twice before running dcpromo. This went through without any specific error.
The problem now is the following: Whenever I try to open the Exchange Management Console, it complains about the old DC cannot be reached ("Active Directory Replied: The LDAP Server is Unavailable"). I cannot change the Configuration-DC either,
when I thry this I get the same error.
I've read http://social.technet.microsoft.com/Forums/exchange/en-US/fbf5bacb-8992-433f-a10a-fadc7a86fab4/exchange-2010-keeps-changing-its-default-preferred-domain-controller and http://social.technet.microsoft.com/Forums/exchange/en-US/fbf5bacb-8992-433f-a10a-fadc7a86fab4/exchange-2010-keeps-changing-its-default-preferred-domain-controller,
I've set DomainController, StaticConfigDomainController,StaticDomainControllers, StaticGlobalCatalogs to the new FQDN and StaticExcludedDomainControllers to the old one.
I deleted "%userprofile%\AppData\Roaming\Microsoft\MMC\Exchange Management Console".
I've checked that the old DC is not Listed alongside the other DCs in "Active Directory Sites and Services" - it isn't.
The output of "get-exchangeserver <name> -status" does not show the old FQDN, except for the EntryStaticExcludedDomainControllers.
By the way: Exchange seems to run well, I can login to Outlook and OWA without problems.
Are there any other things I could do?