Exchange 2010 - visibility of items in Public Folders

Question

Hello all,
I already posted this question to the German Exchange 2010 forum, but have not gotten an answer yet. So I hope to be more lucky in the English forum.
Environment: Exchange 2010 SP3 RU4, 2 replicas for Public Folders, Outlook 2007 cache Mode
Problem:
Some of our users have a phenomenon when working with mail enabled Public Folders:
User has the focus set to Public Folder A, an email is sent there (and correctly delivered) but remains invisible to the user. When he changes the focus to point to his inbox or to Public Folder B and directly changes back to folder A he can see the email.
Other users can see the email directly on delivery without leaving the folder first.
When an affected user adds Public Folder A to his Public Folder Favorites he can see that an email is delivered from the change in numbers of unread mails (number in brackets behind folder name).
I already checked the Exchange server to see if there is a replication related problem (though the default Public Folder DB is the same for all mailbox databases). Even after a successful replication an effected user does not see the email unless he leaves
the folder and re-opens it.
As the problem does not affect all users having permissions to this folder I picked one affected user and tried to remedy the issue as follows:
- deleted the existing Outlook profile and re-created it => without success
- deleted the user profile and re-created it => without success
We use Outlook Cache Mode (set by policy, so the user cannot deactivate it) but there is no Public Folder data downloaded.
When I create a new mail enabled Public Folder to test the scenario with an affected user everything works without problems, he can see an email on delivery.
As far as I know this problem occurs with only two folders (and for both folders only a few users are affected - different users for each folder) I do not know what else to do. Can someone please give me a hint where to look at? Thanks in advance.
Kind regards,
Klaus

Answer 1

The user is caching the public folder.  When he changes the focus and goes back, it tells Outlook to update.  In my experience, I've seen that Outlook only gets the update notices for the primary mailbox, so cached shared mailboxes are generally
rarely updated.  We have stopped caching shared mailboxes for this reason and others.  Think of the following scenario:
Ten different users perform actions on items in a shared mailbox
When they first get the message, they move it to a subfolder in the mailbox (so it won't be there for other users)
Since users are working in Cached mode, they will see an out-of-date image of the mailbox - they will move the item in their copy of the mailbox, but that won't be reflected in the other mailboxes until their copy updates to the server, then the server updates
the other copies.  Talk about being lagged ...