After installing the first Exchange 2010 Server in an Exchange 2007 environment, I noticed the public folders weren’t replicating. Even after adding a number of replicas the hierarchy wasn’t even showing up.
After much searching I found this comment in a blog entry with the solution. Basically, it was due to an object still remaining in Active Directory from Exchange 2003 days.
Using ADSIEdit open “Configuration-Services-Microsoft Exchange-<Organization Name>-Administrative Groups-<Name of your Admin Group>”
In this container delete the object “Servers”.
(Before doing this you should probably back up your AD ;) )
After a little waiting, all was back to normal.