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SteveZX

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Some Outlook 2007 clients switching to wrong GAL!

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We are migrating users from a legacy Windows 2003 forest to a new 2008 forest.  These users need to retain access to their legacy Exchange 2007 e-mail system rather than using the new forest's Exchange 2010 platform.  Full forest transitive trusts are in place.

We disable the legacy AD account, and From Exchange 2007 EMS, we disable the mailbox. Then we reconnect the mailbox to the legacy account, setting the LinkedMasterAccount attribute as follows:

Connect-Mailbox -Identity "/o=OurCompany/ou=Exchange Administrative Group (FYD11BO223SPDLT)/cn=Recipients/cn=mailboxname" -User OldForestADaccount -Database MailboxDatabase -LinkedDomainController newforestDC -LinkedMasterAccount NewForestADaccount -LinkedCredential(get-credential)

The new forest AD account already has an Exchange 2010 "stub mailbox" in place.  Outlook (2007) will point to this if we allow autodiscover/configure.  If we manually configure server settings, we can set the user to point to the correct legacy server & mailbox.

We received reports of NDRs being returned when a small number of migrated users were replying to messages received from Exchange 2010 users.  On checking the GAL for these users, it transpired that their Outlook profile was displaying and resolving to the 2010 GAL!  The only temporary fix we have found for this has been to delete the mail profile and recreate it.  However, a few hours later the problem returns!

OWA works fine and this only seems to be an issue with Outlook 2007 SP3 clients.  We have tried running in cached and online modes with the same results.

Does anyone have any experience/recommendations they can offer?

Many thanks

Steve
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Manpreet SIngh Khatra
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You will have to disable Autodiscover through Registry on the client and create a Host entry in the Host files and then create a Outlook profile with the server you want.

- Rancy
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SteveZX

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Thanks Rancy - we originally disabled autodiscover through GPO, but this had a negative effect on Exchange 2007 functionality (eg: Out of Office Assistant will no longer work from Outlook).  We've since had to re-enable this therefore..  We've tried to avoid the host entry option, as this isn't a very elegant solution, but potentially this may work.  We'll try this on a test machine..

Steve
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Manpreet SIngh Khatra
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Creating a host entry forcing autodiscover to point to the legacy CAS server seems to have done the trick - users who were previously switching back to the 2010 GAL are now retaining their link to the 2007 GAL.  

However, all of the "fixed" users are now receiving a security alert on Outlook startup - "The name on the security certificate is invalid or does not match the name of the site" for the redirected autodiscover server name.  I guess that this is expected behaviour in light of the fix we've applied.  Can you advise if there is a way to resolve this or if we'll have to learn to live with it?

Best regards

Steve
I guess this is more cause the Mailbox is on the New Server and Pointing to the New CAS and i would like to stay put as if i make changes now it could affect users and again once i am ready to move to E2k10 i would have to rerun into all problems .... as of now once your ready you just need to remove the Host entry and work your way out.

- Rancy