Have been using Outlook and Exchange 2013 for few years. Task were getting distributed and updated in sender's folder. Now suddenly behavior of Outlook changed. Task gets distributed. But when receiver updates the tasks, sender gets 'Task Update' email with task item as an attachment and senders task do not get updated. If you try to open 'Task Update' email, you get error showing 'Sorry, we are having trouble opening this item. This could be .........'. Any help ?