Here are a couple of interesting things to be aware of when implementing Exchange 2010 with Outlook 2003 clients. Note that the issues described here do not occur with Outlook 2007 or 2010.
Make sure Outlook 2003 has Office 2003 Service Pack 3 applied. If you don’t it will not work.
Encryption must be enabled in the Outlook profile.
Under the Outlook Profile, choose “more settings” and then choose the Security tab. Make sure “Enable encryption between Outlook and the Exchange Server” is ticked.
Outlook 2003 in Online Mode
An issue exists where Outlook 2003 clients are slow when configured in Online mode. Users will notice things like moving items between folders and deleting items are slow (the item doesn’t move immediately). Cached mode resolves this issue or alternatively you can follow these steps. Note that this fix does not completely resolve the issue, but it does improve performance of Outlook 2003 online mode a lot.
On the server with the Client Access Role
- Install Exchange 2010 Update Rollup 1 and restart the server.
- Now make the following registry change.
- Create a DWORD called ”Maximum Polling Frequency” (without quotes)
- Make the value 10000
Note that this change is dynamic and clients will need to close and open Outlook again for the change to take affect.
Another things you can do to reduce the user impact include:
- turning off the preview pane.
- advising users to open the message and delete the open message, rather than deleting from the Inbox.
I haven’t found a full solution to this problem, but it appears that users with cached mode on Outlook 2003 can get corruption in OST file or Outlook profile. To resolve this issue I have tried to deleting to OST file and creating a new Outlook profile. This works about 75% of the time.
An interesting side-effect of this issue is the Offline Address Book doesn’t download updates. I’ll post more details once I have the answer!