After installing Exchange 2010 and migrating all my DCs to new virtualized 2008 R2 vms and demoting the old DCs, my ESM was sporadically not able to query information. I found there was a registry key on my servers with the management tools that kept the old DC cached for LDAP lookups.Querying anything in the EMC results in MSExchange Configuration Cmdlet - Remote Management, Event ID 5. Oddly it works in the EMS.I changed the DC to a valid and current DC in the following key and it fixed the issue as I couldn't find the setting in the EMC.HKEY_CURRENT_USER\Software\Microsoft\ADs\Providers\LDAP\Hope this helps when someone demotes a DC with Exchange 2010!

Please post this under EXCHANGE 2010 FORUM http://social.technet.microsoft.com/Forums/en/exchange2010/threadsVinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|

Could only find the Exchange 2010 BETA forum and this is RTM, just remove the post.