I am busy doing the exchange 2003 - exchange 2010 transition in a lab setup, and currently the two are running in coexistence. In the lab setup I have 2 DC's, exch2003 server, exch2010 server and a terminal server to do the end user testing. All are running as VM's in MS Hyper-V. So far its been running smooth, I've moved a mailbox across and can send from the moved mailbox to legacy mailboxes (I had to manually create the 2003 <> 2010 connector). Earlier I ran into an issue though : When I attempt to create a new outlook profile, outlook is unable to match the (valid) name I put in to a name in the address list. I have checked, the mailbox is not hidden. The mailbox that I have moved across to the exch2010 server is resolved successfully, and when opened it can see the entire GAL for the company in the address book.

Ok upon further investigation it seems only some legacy users can matched to names in the address list. Doesn't make much sense...

So you are able to create new Outlook profile for newly created Exch 2010 users, but not for the moved mailboxes, is that correct? Can you update the existing Outlook profile for these affected users? Or send email to the affected users? I would suggest you verify the legacyExchangeDN of the moved users, and add X500 address for the moved mailbox. See http://social.technet.microsoft.com/Forums/ar/exchange2010/thread/2ac1b90f-f7fe-478e-9973-4a5c705b28f0. Hope it is helpful. Fiona

any update?Fiona

Thanks for your reply, and sorry for being late with mine, but I do have an update. What we found out is that these same mailboxes that outlook could not match to a name in the address list, also could not be moved over successfully from the exch2003 mailstore to the exch2010 server. The problem, and fix is described in this article : http://support.risualblogs.com/blog/2010/01/18/insufficient-access-rights-to-perform-the-operation-error-when-moving-a-mailbox-onto-exchange-2010/ and http://thoughtsofanidlemind.wordpress.com/2010/10/08/ex2010-insufficient-access/ It turned out to be a permissions issue. All I had to do was to check the "inherit permissions from parent" box in the user account properties > security tab > advanced window, which applies new permissions to the user object which were all exchange permissions when I actually checked what exactly was added. I did not need to follow the other steps in that article to fix my issue. When I had done this outlook was able to resolve the previously problematic accounts to a name in the adress list, and I could successfully move across the problematic legacy mailboxes to 2010. I suspect the reason for this might have something to do with the fact that we changed from SBS to a standard windows+exchange environment a couple of years ago

THanks for your upate and sharing, it is nice to know the resolution and process. Have a good day :)Fiona