The following script demonstrates how you can access System Level Public Folders (Non_IPM_Subtree) using the EWS Managed API and shows how to report on the status of the OAB (Offline Address Book) distribution folders. (Note on 2010 you can also do this with the Exchange Management Shell). It produces a CSV report like The main script is based around the how to series template but because there is no enumeration to get to the Non_IPM_Subtree one trick is needed. The first thing is to bind to the normal Public Folder Root using PublicFoldersRoot Enum then use the ParentFolderId property of this folder to bind to the parent then search for the Non_IPM_Subtree folder which will be a subfolder of this folder. Then you can query for any System Folder from this point in this example it finds the OAB folder queries for any subfolders under this folder and then finds any of these subfolders with Items and queries the size, number of Items and the Modified date of the last item. I'