Recently, I’m experiencing issue with IMAP Sync troubles with my Outlook2013. Many articles point to the direction on the update KB2837618 and KB2837643 were released by Microsoft on 12 Nov 2013 that might have caused the hiccups. However, I don’t recommend un-installing these updates as they add some IMAP improvements and you’ll have a better IMAP experience with these updates.
I personally recommend these methods;
The first, and I reckon this is the most effective method is to add Inbox to the IMAP root.
To do this, go to File, Account Settings and double click on your affected IMAP account. Click “More Settings” button then switch to the “Advanced” tab.
In the Root folder path field type Inbox. Exit the dialog and perform a send and receive.
However, there are 2 things you need to take note of;
a. If the Inbox is not your root folder, setting Inbox as the root won’t work, as it will hide all of the other folders.
b. The rules and alerts with folders specified will be disabled due to errors that these locations are no longer exist.
If that doesn’t work, try disabling the option to show only subscribed IMAP folders.
Right click on the IMAP Inbox folder and choose IMAP folders. At the bottom of the dialog is an checkbox for When displaying hierarchy in Outlook, show only the subscribed folders. Remove the check then close the dialog to return to Outlook. Click Send and Receive.