I am currently following the guide http://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/A_2881-Migrate-Small-Business-Server-2003-to-Exchange-2010-and-Windows-2008-R2.html
I am at stage 6 -install exchange 2010. I want my 2010 exchange to run alongside exchange on my sbs for a few days, This is so I do no need to manually update client's outlook.
However to do this, do I need to migrate the mailboxes from my sbs2003 to my new exchange server, or can I have them both up and running and then do it.
I was hoping to install exchange 2010, have it running alongside the sbs2003, with email still going through the sbs2003, and then manually migrate a few mailboxes to test if Outlook works.