Several days ago I noticed that a subfolder normally in existence beneath the Inbox folder on the pane on the left  side of the main page was no  longer present. I utilized this subfolder by simply right clicking on on email on the Inbox main page, and dragging that email to the subfolder. There are a number of emails that are important to me and I'd like to know why this occured and how do I get the subfolder, with all of the emails therein, back?