If you recently set up a new IMAP account in Outlook 2013 and some of your messages or folders are missing, follow these steps to synchronize your mail account.
Step 1 - Select the Inbox of your mailbox. From the "Folder" menu, select "IMAP Folders".
Step 2 - From the IMAP folder dialog box, uncheck the box next to "When displaying hierarchy in Outlook, show only the subscribed folders." Click Apply to save the changes.
Step 3 - Click OK to close the IMAP folder dialog box
Step 4 - From the "Home" menu, click the Send/Receive button to force Outlook to sync all missing folders.
See below for screen shots.
Posted July 15, 2014