PST won't open after adding MSG files

I created a PST file using the ASPOSE EMail API and then add MSG files using the same API but when I try to open the file in Outlook, I get an errorERROR:Cannot expand the folder. Windows Search exitied without properly closing your Outlook data file. I've attached a screen shot of the error.Here is some of the code I'm using.

  Aspose.Email.Outlook.Pst.PersonalStorage pst = Aspose.Email.Outlook.Pst.PersonalStorage.FromFile(@"c:\temp\temp.pst" );
   Aspose.Email.Outlook.Pst.FolderInfo fi = pst.RootFolder;

  foreach (var folder in folders)
          {
             
              FolderInfo lookup=  fi.GetSubFolder(folder);

                    if (lookup == null)
              {

                  fi = fi.AddSubFolder(folder);

              }
                    else
                    {
                        fi = lookup;
                    }

 fi.AddMessage(Aspose.Email.Outlook.MapiMessage.FromFile(exportItem.ExportFilePath));  Aspose.Email.Outlook.Pst.PersonalStorage pst = Aspose.Email.Outlook.Pst.PersonalStorage.FromFile(@"c:\temp\temp.pst" );
   Aspose.Email.Outlook.Pst.FolderInfo fi = pst.RootFolder;

  foreach (var folder in folders)
          {
             
              FolderInfo lookup=  fi.GetSubFolder(folder);

                    if (lookup == null)
              {

                  fi = fi.AddSubFolder(folder);

              }
                    else
                    {
                        fi = lookup;
                    }

 fi.AddMessage(Aspose.Email.Outlook.MapiMessage.FromFile(exportItem.ExportFilePath));