You are trying remove Exchange 2003, but you get an error similar to “you cannot remove a server that is a target bridgehead for a routing group connector. This server is a target bridgehead for the following connections”.You have removed the connector in ESM.
You have run the Remove-RoutingGroupConnector command on the Exchange 2007/2010 servers
(If you struggle with this step and get an error because you have bi-directional connectors, such as: Remove-RoutingGroupConnector : The operation could not be performed because “RGC NAME” matches multiple entries. Run this command:
get-routinggroupconnector -Identity “RGC NAME” |Remove-RoutingGroupConnector)
You still continue to get the error on the 2003 server.
You have checked in ADSI Edit and the connector isn’t there.
Have you checked the exchange services? Did you disable them for a while to check that Exchange would be OK to remove from the environment? Are they still disabled?
Re-enable them, and start them up. You should be able to remove Exchange 2003 now.