Outlook 2013 shows only Online Archive while connected to Office 365

This is just a quick heads up. It started to happen in some environments after last Office 2013 patch in mid January 2015. When Outlook 2013 is restarted after patching, it shows only Online Archive, no primary mailbox and user is unable to send e-mails.

Root cause:

It has not yet been defined, however fix is to disable MAPI over HTTPS on affected client, so I suppose it will be network device, which does not understand MAPI over HTTPS protocol.

Temporary fix:

When changing the below registry key (disable MAPI/HTTP and re-enable RPC/HTTP), the problem disappears:

HKEY_CURRENT_USER\Software\Microsoft\Exchange\MapiHttpDisabled = 1 DWORD

 Permanent fix:

Install Exchange 2013 CU7.