Exchange 2010/Domain Controller combo server running on Windows 2008 R2.
Demote Domain Controller role, causes Exchange Management Console fails to retrieve any Exchange information with error message “Active directory response: The LDAP server is unavailable.” It’s still looking for the demoted controller although it’s been cleaned out of AD/DNS. All Exchange services start fine, and Exchange Shell works fine.
The obsolete information is cached in an Exchange Management Console file in the Windows profile for the user. EMC is trying to connect to orginal DC that is stored in the file.
Go to the following folder and delete the Exchange Management Console file.
C:\users\<specific user>\AppData\Roaming\Microsoft\MMC\Exchange Management Console
Close EMC and reopen it.