I have a client with 10 users currently running SBS2003 and use Exchange 2003, but not sharepoint or SQL Server. We are preparing to move to Server 2012 Standard R2 and Exchange 2013. I know I cannot migrate from Exchange 2003 to Exchange 2013 easily, so I think I have 2 options. Option 1 would be to bring the Server 2012 r2 online as part of the current domain, move the data files over from the old server to the new server. Then export the 10 mailboxes out to PST files. Shutdown SBS2003, install Exchange 2013 on the new server and import the PST files back into Exchange 2013. Option 2 is to just build a new domain on the new box, create the users, install Exchange 2013 and make sure that all works, then export the Exchange 2003 mailboxes to PST files, connect the workstations to the new domain and import the PST files back into Exchange 2013. I have three questions: 1 - Which is the better option; 2 - What are the steps for the best option; 3 - while MS does not recommend it, is it possible to run Exchange 2013 on the same box and what are the drawbacks of doing that?