We are going to have a problem when we move to Exchange 2010 with our Outlook 2010 clients that are at the end of a 1Mbps WAN link. We have around 60 laptop users who have mailboxes between 500MB and 8GB, and when their mailboxes are moved to the new mail database and the new CAS arrays. When we recently implemented new laptops and Windows 7/Office 2010, one site took 2 weeks at 95% WAN consumption until all email was cached by clients. 1. Will the email need to be re-cached by the users? Will they loose the contents of their OST and have to download it all over again? 2. Is there a way to take a copy of the Exchange 2010 mailstores over to the remote site to allow them cache their mail? We could build up a laptop with a passive replica within the DAG and then bring it online in the remote site - but will this work with IP address changes, and the database copy being offline for an extended time whilst that Exchange 2010 laptop is shipped around from remote site to remote site? Thanks for any helpful advice.

1: Yes as they changed there Workstation. 2: You can export the PST and give it to End users, thats the option you have. If you have so many things in the environment than you should use Online Mode rather than Cached Mode... Else Increase the bandwidth. Gulab | MCTS-MCITP Messaging: 2010 | MCTS-MCITP Messaging: 2007 | MCC 2011 | Skype: Gulab.Mallah

Thanks for your reply. 1, No they have not changed their workstation, or their profile - this is for users who are currently connected to Exchange 2007, and then their mailbox is moved to Exchange 2010 - will this require that the user re-downloads all their email again? 2. I will see if we can find a way to export to PST - unless there is a tool to convert an OST to a PST and then import that back in? Online mode uses more bandwidth in day to day operations, which is why we use Cached mode. This is also why we have slow WAN links - normal activity (with cached mode) only needs a slow link. I will investigate if we can temporarily increase our bandwidth.

Hi Christian, If the mailboxes are moved in the same exchange organization, they would not re-downloads the email again. Could you please post more detailed information about your mifration, then we could do more research about it. I am a little confused about below: 2. Is there a way to take a copy of the Exchange 2010 mailstores over to the remote site to allow them cache their mail? We could build up a laptop with a passive replica within the DAG and then bring it online in the remote site - but will this work with IP address changes, and the database copy being offline for an extended time whilst that Exchange 2010 laptop is shipped around from remote site to remote site? If you want to use the DAG to achieve the target, it is too much complicated, and not suggested. like my above referred, if all the exchange 2007 server and exchange 2010 server in the same exchange ORG, we could do it. there is no affact to users. Regards! Gavin TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please 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.