A user added a secondary mailbox of another user in Outlook 2013 after permissions where added via the 365 portal , however the only folder showing for the shared mailbox was clutter.

I logged the user into 365 webmail and opened the shared mailbox via web and it showed all folders proving permissions were fine.

I removed the permissions via powershell and re-added with Automapping to $false as it seems like this can cause problems with Outlook 2013 however did not resolve the problem.

I turned off cached mode and restarted Outlook and it displayed all folders. After deleting the OST and re-creating it , the folders showed fine