public static Outlook.Application oApp = new Outlook.Application();
    public static Outlook.NameSpace oNS = oApp.GetNamespace("MAPI");
    public static Outlook.MAPIFolder RootFolder;
    public static void CopyMessages()
    {
        string folderName = "emails";
        string strFileName = @"C:test.pst";
        string strDisplayName = "PST";
        Outlook.MAPIFolder inBox = oApp.ActiveExplorer().Session.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderInbox);
        ThisAddIn.oNS.AddStore(strFileName);
        RootFolder = ThisAddIn.oNS.Folders.GetLast();
        RootFolder.Name = strDisplayName;
        //ThisAddIn.oNS.RemoveStore(RootFolder);
        //ThisAddIn.oNS.AddStore(strFileName);
        try
        {
            inBox.Folders[folderName].CopyTo(RootFolder);
            //System.Threading.Thread.Sleep(2000);
            ThisAddIn.oNS.RemoveStore(RootFolder);
            //ThisAddIn.oNS.AddStore(strFileName);

        }
        catch
        {
            MessageBox.Show("There is no folder named " + folderName +
                ".", "Find Folder Name");
        }
    }