Q: Can you run Exchange Server 2010 with Windows Server 2016 Domain Controllers?
The Exchange supportability matrix is once again, used as a reference and once again, you must be very clear on what you are reading. Since there is NOT an ‘x’ in the intersection of Exchange 2010 and Windows DFL/FFL 2016 in the Supported Active Directory environments table, then it is NOT supported.
I know many people think that the Exchange PG just forgot to put in the X. But the point is clear, they have NOT tested, nor do they plan to test, having Exchange Server 2010 versions in an Active Directory that contains any Windows Server 2016 DC’s. Not in another AD site, not in a different domain, nothing, nowhere in the AD Forest that contains Exchange servers.
However, what about the AD Schema? That is supported oddly enough. While not at all listed on the go to reference of Exchange Supportability page, it is supported. This also occurred in Windows AD in general when you could extend the schema for GPO attributes for say Windows 10 clients, but the DC’s were still 2003 or 2008R2 for example. Having empty database attributes, is not the issue. The issue is how DC’s would communicate, or not communicate correctly to non-tested applications.
Therefore, if you still have Exchange 2010 servers in your environment, do NOT update the Domain Controllers beyond 2012R2 Windows Server Operating System.