I have noticed that since upgrading to Office 2013, Outlook 2013 is consuming huge amounts of data, around 750MB per hour. I keep my IMAP mailboxes empty as much as possible and store everything locally.
I tried disabling my two IMAP accounts in Outlook and it stopped. I also tried disabling each of them individually and it still didn't stop. I have checked with my e-mail hosting provider, and they have confirmed that they can likewise see the excessive
traffic from my IP address at their end.
What is causing this excessive data consumption and how do I prevent it? Are there any further diagnostic steps I can carry out?