We recently upgraded our Exchange 2003 environment to a new Exchange 2010SP1 environment, and replicated all public folders to this new environment. We decommissioned all Exchange 2003 servers, and everything works well, except that we have some cosmetic sync issues in our Outlook clients in cached mode (=known problem). In one of the document about these sync issues, someone mentioned checking the EFORMS REGISTRY-public folder. Now when I check the replica's of the system folders in the new Exchange 2010 environment, the 3 system folders (written in CAPITALS) EFORMS REGISTRY, OFFLINE ADDRESS BOOK and SCHEDULE+ FREE BUSY have no replica's at all. However, the subfolders in these 3 folders do have replica's on all public folder servers. If I try to add a replica to one of these 3 capital folders, I get an error message "Modification of the '\NON_IPM_SUBTREE\EFORMS REGISTRY' folder isn't allowed. Is this something I should be worried about or is this working as designed?