Exchange 2010 public folders not forward emails or tasks

When you've migrated from Exchange 2000 or Exchange 2003 to Exchange 2010 and have decommissioned the older servers, you can run into a situation where your public folders won't accept or forward emails. There are already several posts regarding this on the Internet, but all the ones I've seen were either for email public folders or public folders accepting emails. However, it affects non-email public folders from forwarding emails as well.

The first thing is to see if a public folder will accept an incoming email. If you don't have one set up for it, set up a test folder. Send an email to it and you should an NDR saying:

554 5.2.0 STOREDRV.Deliver.Exception:ObjectNotFoundException; Failed to process message due to a permanent exception with message The Active Directory user wasn't found. ObjectNotFoundException: The Active Directory user wasn't found. ##


This issue is caused because Exchange will look at all Exchange server AD containers, including the empty Exchange 2000/2003 container, for a System Attendant to process the message, and errors out on the empty container. The solution is to delete the empty container using ADSIedit. As always, be very careful using ADSIedit as you can cause a lot of damage. If you see any servers in the container STOP because you're probably looking at the 2010 container. Once it's deleted, give Exchange 2010 some time to see the change and start processing correctly.