When connecting Outlook to IMAP from Telenor (online.no) the Inbox was empty; only Sent items were available.
This is because Telenor have all the folders under the Inbox. You can see this by right clicking on the Inbox and choosing IMAP Folders. You will then see, Inbox, Inbox.Drafts, Inbox.Sent and so on
To fix this you need to set the Root folder path setting to Inbox
Open Outlook then click on File, Account Settings, then Account Settings again.
Click on your (Telenor) IMAP account and click Change
Click More Settings ... then Advanced
Under Folders it should say Root folder path:
Type Inbox
Click OK and continue to exit out of the dialogue boxes
The Inbox should now synchronise as normal.