Office team has released an update for Outlook 2007 which addresses the performance problems customers have reported to us, especially when working with large .PST and .OST files. We highly recommend applying this patch on all systems with Outlook 2007 installed.
Refer to the following KB article for more details about the problem that has been fixed in this update:
932086 You may experience performance problems when you are working with items in a large .pst file or in a large .ost file in Outlook 2007
As this update is not available in Microsoft Update or Office Update, you may need to download it directly from the Microsoft Download Center at:
Update for Outlook 2007 (KB933493)
Please note: If you are using Microsoft Outlook Business Contact Manager (BCM) – there is a known issue. Refer to the following KB article for more information::
935569 Error message when you start a 2007 Office program on a computer that is running Outlook 2007 with Business Contact Manager: "Office application version does not match"
For more information about this update, refer to:
933493 Description of the update for Outlook 2007: April 13, 2007