 <p>Most likely the folder variable is null - if the folder does not exist, retrieving it by name (<code>RDOFolder.Folders.Item("foldername"))</code> will return null:</p> <pre><code>RDOSession session = new RDOSession(); RDOPstStore store = session.LogonPstStore(newpstpath); RDOFolder folder = store.IPMRootFolder.Folders.Item(directoryEmlFile); if (folder == null) folder = store.IPMRootFolder.Folders.Add(directoryEmlFile); RDOMail mail = folder.Items.Add("IPM.Note"); </code></pre>