I just got a nasty surprise from my server administrator. From 26th November until 30th November, I used 140 GB of traffic on my mailserver. The first four days of December I used another 100GB of traffic.
We narrowed the traffic down to port 993, which is the port I use to aquire mails from the mailserver. Apparently Outlook 2013 kept resyncing my 4GB mailbox several times a day. There was nothing visible happening in outlook, the only way to discover it was to monitor inbound traffic on the mailserver (or outbound traffic on the computer).
If you google "outlook 2013 bandwith" there are numerous accounts from people who have had problems with the way Outlook 2013 works with IMAP.
I have used Outlook 2013 and IMAP since this June with no apparent problem. But since 26th of November, the bandwidth consumption just went crazy! Apparently that same day, Office was automatically updated to version 15.0.4551.1005.
As suggested on the sites where others have experienced this problem, I have managed to stop the problem by deleting my account and recreating it. But according to others this will only provide a temporary relief. The next issue is, that I have to prevent other users of the mailserver from using Outlook 2013 with IMAP, because it becomes extremely expensive when this issue appears and the user has a broandband connection.
Is Microsoft aware of this bug, are there any plans for releasing a fix? If so, when? If not, why not?
I have never had issues with other versions of Outlook on this mailserver, and I have at least one other user who has Outlook 2013 with IMAP account on the same server, but no apparent problem with bandwidth consumption yet.
The latest update for Outlook (http://support.microsoft.com/kb/2837618) brought quite some changes to IMAP which required the cache to resync with the mail server and also for you to set a root folder path if the server actually requires it.
The endless synchronization seems to occur in some extreme cases were recreating the mail account in Outlook should provide relief.
If it still happens then, make sure you are not running a local add-in which modifies the message upon receiving it and thus causing it to immediately sync back to the server again as well. Especially virus scanners which integrate themselves with Outlook are often a cause of repeatedly synchronizing IMAP accounts. See: Disable virus scanner integration?
Additionally see: Empty Inbox and other IMAP synching issues in Outlook 2013
- Marked as answer by Melon Chen CHNMicrosoft contingent staff, Moderator Sunday, December 15, 2013 1:34 PM