We had problems with Exchange 2003 server after transferring FSMO roles from the DC server to a different DC server and demoting the original server to a basic file server (Exchange server was completely separate i.e. not a DC).
The process of transferring FSMO roles and demotion as described in these MS articles:
went through without any problems but later in the day we had reports from Exchange users that they could not get email – Exchange server was acting erratically and eventually services stopped altogether.
It transpired that the Recipient Update Server (RSU) was at fault. The RUS needs to use a Global Catalog server (typically there is only one per domain). It was looking at the old server for the Global Catalog. I tried to change it to the correct server but ran into an error when trying to select the DC stating ‘The operation failed. ID no 80004005 Exchange System Manager’.
I checked there were no rogue records in AD of old DC servers using Petri’s excellent article: http://www.petri.co.il/delete_failed_dcs_from_ad.htm, but no old servers were listed.
As I could not change the RUS settings through the system manager I looked for another way to change them and found this solved the problem:
Open ADSI Edit and navigate to ConfigurationServicesMicrosoft Exchange<Organization Name>Address Lists ContainerRecipient Update Services.
On the right side, you will see the RUS links listed.
Right click on the relevant RUS and select Properties.
Where you see “Select a property to view:” select msExchServer1NetworkAddress.
You should see the current Domain Controller listed.
Click on the Clear button
Change to correct server and click Set and OK
Restart the Microsoft Exchange System Attendant Service