Hello all..I`m trying to uninstall the Active node of this SCC cluster with Windows 2003, the passive node uninstall without any problems but with the active one i`m getting this error (The Clustered mailbox server removal cannot continue: Object refrence not set to an instance of an object.).looking in ExchangeSetup.log i found that the server name appears to look the cause of the problema so i checked in AD and DNS and the servername looks fine.This is the last part in ExchangeSetup.log:[9/4/2009 10:50:00 AM] [0] **************[9/4/2009 10:50:00 AM] [0] Setup will run the task 'test-setuphealth'[9/4/2009 10:50:00 AM] [1] Setup launched task 'test-setuphealth -DomainController 'dc.server.local' -DownloadConfigurationUpdates $true -ExchangeVersion '8.1.240.6' -Roles 'ClusterMailbox' -ScanType 'PrecheckUninstall' -SetupRoles 'ClusterMailbox','Mailbox','AdminTools' -CmsName 'GREENSKY'' [9/4/2009 10:50:00 AM] [1] Beginning processing.[9/4/2009 10:50:06 AM] [1] Beginning processing.[9/4/2009 10:50:06 AM] [1] Administrator Active Directory session settings are: View Entire Forest: 'True', Configuration Domain Controller: 'dc.server.local', Preferred Global Catalog: 'dc.server.local', Preferred Domain Controllers: '{ dc.server.local }'[9/4/2009 10:50:06 AM] [1] Searching objects "GREENSKY" of type "Server" under the root "$null".[9/4/2009 10:50:06 AM] [1] Previous operation run on domain controller 'dc.server.local'.[9/4/2009 10:50:06 AM] [1] Dumping the cluster named: .[9/4/2009 10:50:06 AM] [1] Groups[9/4/2009 10:50:06 AM] [1] [WARNING] An unexpected error has occurred and debug information is being generated: Object reference not set to an instance of an object.[9/4/2009 10:50:06 AM] [1] [ERROR] Object reference not set to an instance of an object.[9/4/2009 10:50:07 AM] [1] Beginning processing.[9/4/2009 10:50:07 AM] [1] Administrator Active Directory session settings are: View Entire Forest: 'True', Configuration Domain Controller: 'dc.server.local', Preferred Global Catalog: 'dc.server.local', Preferred Domain Controllers: '{ dc.server.local }'[9/4/2009 10:50:07 AM] [1] Searching objects "GREENSKY" of type "Server" under the root "$null".[9/4/2009 10:50:07 AM] [1] Previous operation run on domain controller 'dc.server.local'.[9/4/2009 10:50:07 AM] [1] Dumping the cluster named: .[9/4/2009 10:50:07 AM] [1] Groups[9/4/2009 10:50:07 AM] [1] [WARNING] An unexpected error has occurred and debug information is being generated: Object reference not set to an instance of an object.[9/4/2009 10:50:07 AM] [1] [ERROR] Object reference not set to an instance of an object.[9/4/2009 10:50:07 AM] [1] Beginning processing.[9/4/2009 10:50:07 AM] [1] Administrator Active Directory session settings are: View Entire Forest: 'True', Configuration Domain Controller: 'dc.server.local', Preferred Global Catalog: 'dc.server.local', Preferred Domain Controllers: '{ dc.server.local }'[9/4/2009 10:50:07 AM] [1] Searching objects "GREENSKY" of type "Server" under the root "$null".[9/4/2009 10:50:07 AM] [1] Previous operation run on domain controller 'dc.server.local'.[9/4/2009 10:50:07 AM] [1] Previous operation run on domain controller 'dc.server.local'.[9/4/2009 10:50:07 AM] [1] Preparing to output objects. Maximum result set size "unlimited".[9/4/2009 10:50:07 AM] [1] Ending processing.[9/4/2009 10:50:07 AM] [1] [ERROR] The clustered mailbox server removal cannot continue: Object reference not set to an instance of an object.[9/4/2009 10:50:07 AM] [1] Ending processing.[9/4/2009 10:50:07 AM] [0] **************[9/4/2009 10:50:07 AM] [0] Setup will run the task 'test-setuphealth'[9/4/2009 10:50:07 AM] [1] Setup launched task 'test-setuphealth -DomainController 'dc.server.local' -DownloadConfigurationUpdates $false -ExchangeVersion '8.1.240.6' -Roles 'Mailbox' -ScanType 'PrecheckUninstall' -SetupRoles 'ClusterMailbox','Mailbox','AdminTools' -ActiveCmsUninstall $true -TargetDir 'C:\Program Files\Microsoft\Exchange Server' -IISInstalled $true' [9/4/2009 10:50:07 AM] [1] Beginning processing.[9/4/2009 10:50:12 AM] [1] Beginning processing.[9/4/2009 10:50:12 AM] [1] Dumping the cluster named: .[9/4/2009 10:50:12 AM] [1] Groups[9/4/2009 10:50:12 AM] [1] [WARNING] An unexpected error has occurred and debug information is being generated: Object reference not set to an instance of an object.[9/4/2009 10:50:12 AM] [1] [ERROR] Object reference not set to an instance of an object.[9/4/2009 10:50:13 AM] [1] Beginning processing.[9/4/2009 10:50:13 AM] [1] Administrator Active Directory session settings are: View Entire Forest: 'True', Configuration Domain Controller: 'dc.server.local', Preferred Global Catalog: 'dc.server.local', Preferred Domain Controllers: '{ dc.server.local }'[9/4/2009 10:50:13 AM] [1] Searching objects "EXCSRV01" of type "Server" under the root "$null".[9/4/2009 10:50:13 AM] [1] Previous operation run on domain controller 'dc.server.local'.[9/4/2009 10:50:13 AM] [1] Previous operation run on domain controller 'dc.server.local'.[9/4/2009 10:50:13 AM] [1] Preparing to output objects. Maximum result set size "unlimited".[9/4/2009 10:50:13 AM] [1] [ERROR] Unexpected Error[9/4/2009 10:50:13 AM] [1] [ERROR] The operation could not be performed because object 'EXCSRV01' could not be found on domain controller 'dc.server.local'.[9/4/2009 10:50:13 AM] [1] Ending processing.[9/4/2009 10:50:13 AM] [1] [ERROR] There was a problem accessing the registry on this computer. This may happen if the Remote Registry service is not running; it may also indicate a network problem.[9/4/2009 10:50:13 AM] [1] [ERROR] The clustered mailbox server removal cannot continue: Object reference not set to an instance of an object.[9/4/2009 10:50:13 AM] [1] Ending processing.[9/4/2009 10:50:13 AM] [0] The Exchange Server Setup operation did not complete. For more information, visit http://support.microsoft.com and enter the Error ID.[9/4/2009 10:50:13 AM] [0] End of Setup[9/4/2009 10:50:13 AM] [0] ********************************************** Ariel Antigua | MCSA:Messaging | http://blog.arielantigua.com

Oh, the command i`m running to launch the uninstall is:ExSetup.exe /mode:uninstall /removecms /cmsname:GREENSKY /dc:dc.server.localAriel Antigua | MCSA:Messaging | http://blog.arielantigua.com

Have you successfully removed all roles from this Clustered Maiilbox server? such as Mailbox/PF's etc? also make sure the Remote Registry service is up and runningVinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|

Yes i removed all the Mailboxes and PF's from this server. The remote registry is running for sure i restart it.Ariel Antigua | MCSA:Messaging | http://blog.arielantigua.com

I was using my domain account and decided to start using the administrator account so now there is just one error.C:\Program Files\Microsoft\Exchange Server\Bin>ExSetup.exe /mode:uninstall /removecms /cmsname:greensky /dc:dc.server.local Welcome to Microsoft Exchange Server 2007 Unattended SetupThe following server roles will be removed Clustered Mailbox Server Mailbox Role Management Tools Performing Microsoft Exchange Server Prerequisite Check Clustered Mailbox Role Checks ......................... COMPLETED Mailbox Role Checks ......................... FAILED There was a problem accessing the registry on this computer. This may happen if the Remote Registry service is not running; it may also indicate a networkproblem. The clustered mailbox server removal cannot continue: Object reference notset to an instance of an object. The Exchange Server Setup operation did not complete. For more information, visit http://support.microsoft.com and enter the Error ID. C:\Program Files\Microsoft\Exchange Server\Bin> the error talk about the remote registry not running but it ir running, i check the permisions on regedit and changed the administrator to full and the local service account is read only. Previosly Clustered Mailbox Role check was failing too..Ariel Antigua | MCSA:Messaging | http://blog.arielantigua.com

Well... after a few weeks trying to solve this and remove the CMS from Active Directory the solucion was this:i ran setup.exe /removecms cmsname:greenskyand the CMS just dissapear from the Exchange Management Console but was left on the Schema, using ADSIedit i ended removing it from the schema and my last step was format both members of the Windows 2003 Cluster and install Windows 2008 on it to make the new cluster and install Exchange using another name not the one tha was used on win2k3.Ariel Antigua | MCSA:Messaging | http://blog.arielantigua.com