I remember reading when Office 2010 was release that Outlook 2010 had a negative performance hit on Exchange 2003 servers. Today I went looking for the article I read but haven't been able to find any information to support what I prevously read. We have placed the upgrade of Office on hold because of these concerns. Today I found that Outlook 2003 has end user functionality issue with Exchange 2010. So am wondering if anyone can provide some clarity to this issue? I know what these issues are, but more concern that if we mass deploy Outlook 2010 that I will kill the Exchange 2003 servers. Did anyone have Exchange 2003 performance issues switching their users to Outlook 2010? We have close to 8000 users and I have no plan to build new exchange 2003 servers. I am focusing on the upgrade, but haven't had much luck finding information on the recommended upgrade path for Outlook 2010 when you are tranisioning from Exchagne 2003 to Exchange 2010. Deploy Outlook 2010 before Exchange 2010 deployment or after? Any information is appriciated!

hi, to my opinion, upgrade your outlooks to 2010 before installing exchange server 2010. regards, Mumin CICEK | www.cozumpark.com | Please click Vote As Helpful if it is helpful for you and Propose as Answer!!!

I would suggest upgrading Outlook before Exchange if possible. I am not aware of any performance issues with Outlook 2010 and the older versions, but there are lots of issues with Outlook 2003 and Exchange 2010. To the point where I know of some consultants who recommend against running Outlook 2003 against Exchange 2010. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Thanks for the feedback so far.

Hi, Some issues should be noticed when Exchange 2003 working with Outlook 2010: http://support.microsoft.com/kb/982774 Issue of Exchange 2010 with Outlook 2003 http://support.microsoft.com/default.aspx?scid=kb;en-US;2009942Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.