Sometimes, a problem can temporarily stump even experienced Exchange 5.5 administrators. For instance, your servers all seem to work, your users notice no problems, and yet adding an owner to a distribution list produces the following error:
An internal processing error has occurred: Invalid
Please restart the Administrator program, Microsoft Exchange Server or both.
Microsoft Directory ID: DS_E_INVALID_ATTRIBUTE_SYNTAX
Stopping and restarting the Administrator program or the Microsoft Exchange Directory service doesn't help, and even a system reboot fails to solve the problem.
The distribution list in question works, intersite and intrasite replication function normally, and there aren't any unusual messages in the Event log. All is well—except you still can't add an owner to that distribution list.
The fix is simple. Open the Properties of the distribution list, and you'll see that the value in the Expansion Server field is blank. Select Any Server In Site or choose any desired server from the drop-down list for the Expansion Server field. Once you make this selection, you can add an owner to the distribution list and close the dialog box without encountering an error.