We have Exchange 2010 and a mix of Outlook 2003 and Outlook 2010 clients.

  1. When Exchange Cached Mode is enabled, clients are receiving sync issues. In Outlook 2010, the sync issues are mainly with the Deleted Items. In Outlook 2003, they are mainly around the Offline Address Book.
  2. When Exchange Cached Mode is disabled, the clients notice a 3 second delay in deleting email in list view within the Inbox.

Anyway that these two issues can be resolved? It's a big pain especially to the frustrated end users.


  • 1
    Do you have any new information? Have you been able to solve this? Can you post some of the error messages?
    – Zoredache
    Commented Dec 8, 2010 at 2:45
  • Nothing additional. SP1 was "supposed" to fix it but didn't. Commented Dec 28, 2010 at 16:35
  • Do you have any examples of the sync issues you are getting? Commented Jan 4, 2011 at 13:56

3 Answers 3


ad1) Please be more specific with sync issues. Do messages disappear? Do messages get duplicated?...

ad2) The basic issue is that Outlook 2003 support UDP and polling notifications. Exchange 2007 supports UDP, polling and Async notifications. Exchange 2010 only supports polling and Async notifications. This means when Outlook 2003 move from Exchange 2007 to Exchange 2010, Outlook clients will fall back to polling which by default only gets notifications every 30secs-1min. This means any change won’t show up immediately.

UDP notification support was removed from Exchange 2010. As a result, Outlook 2003 can only use polling notifications in online mode, which are still supported by RPC Client Access. This will result in a slight delay in updates to item status (30 seconds on average up to a 1 minute delay) when changes are made to items in a mailbox accessed by Outlook 2003.

source: http://social.technet.microsoft.com/Forums/en/exchange2010/thread/d5a610d5-b3cd-40a5-8653-634f3b174f4e


See this newly released fix for Exchange 2010: UDP Notification Support Re-added to Exchange 2010. It should help.


We've had a few problems with Outlook Anywhere configuration causing problems with the Offline Address Book. You can use this site: https://testexchangeconnectivity.com/ to check you have everything set up correctly (site is owned by Microsoft)

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