Have a client that I have started migrating from SBS 2003 to W2012. I have joined the W2012 to the somein and it is setup with A/D. Originally I was going to decommission the SBS2003 completely, moving the FSMO roles, remove Exchange and decommission. Now he is setting up a remote office and I would like to keep the SBS2003 machine at the original office for A/D authentication but have most of the files on the new server at the new / larger location.
What is the drawback to removing Exchange from SBS2003, but leaving it run?
Only used for the A/D component for local authentication. He has migrated mail to Office365 and only has 6 users. 4 at new location and 2 at old