Email messages take a long time to send and receive using Outlook 2003 with Exchange 2010

UDP notification support was removed from Exchange 2010. As a result, Outlook 2003 can only use polling notifications in online mode. This will result in a slight delay in updates to item status (30 seconds on average with up to a one-minute delay) when changes are made to items in a mailbox accessed by Outlook 2003. There are two workarounds for this issue:

• Use Outlook 2003 in Cached Exchange Mode.
• Adjust the polling interval on the Client Access server. Note: This will impact the performance of the Client Access server.

To resolve this problem, use one of the following methods.

Option 1: Install Update Rollup 1 For Exchange Server 2010

After you install the update, you must add the following registry data to the server by using the Client Access role.

Start Registry Editor.

Locate and then click to select the following registry subkey:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeRPC\ParametersSystem

Note: Create the \ParametersSystem registry subkey if it does not exist.

Add the following registry data to the server:

Value type: REG_DWORD
Value name: Maximum Polling Frequency
Value data: any integer between 5000 and 120000 (decimal value)

The registry change is dynamically detected. Therefore, the new settings will be applied to any new connections that clients make after the change is made. If you want to make sure that the new settings are applied to all clients, you should recycle the Microsoft Exchange RPC Client Access service because connections from clients can remain alive for a long time.

Outlook 2003 does not poll the Exchange Server 2010 server in intervals that are less than 10 seconds. Therefore, any value less than 10000 will generally have the same effect.

This change does not reinstate UDP communication between Exchange Server 2010 and Outlook 2003. This change only enables polling to occur more frequently between Exchange Server 2010 and Outlook 2003.

Option 2: Use cached mode with your Outlook 2003 profile

If you cannot install Update Rollup 1 for Exchange Server 2010 at this time, use cached mode for your Outlook 2003 profile. The cached mode synchronization process uses a different architecture to update folders that are in your mailbox.

To configure your profile to use cached mode, follow these steps:

1. Exit Outlook 2003 if it is running.
2. In Control Panel, start Mail.
3. Click E-mail Accounts.
4. Click to select View or change existing e-mail accounts, and then click Next.
5. Select your Microsoft Exchange Server account, and then click Change.
6. Click the Use Cached Exchange Mode check box to enable cached mode.
7. Click Next, and then click Finish.
8. Start Outlook 2003.