Messages in IMAP folders are not listed in Outlook 2013
The issue is caused by the following Microsoft updates:
It can be resolved in two ways:
I. Disable the "Show only subscribed folders" option in Outlook
Go to FOLDER -> IMAP Folders
Uncheck "When displaying hierarchy in Outlook, show only the subscribed folders.".
- Force Send/Receive within Outlook.
II. By changing the "Root folder path"
Go to File-> Account Settings-> Account settings->
Problematic IMAP account-> Change...-> More Options...-> Advanced
Set Root folder path to Inbox and force a Send/Receive