Just set up a test environment for MS Exchange as follows: 1 x AD Server, Windows 2012 R2 1 x Exchange 2010 SP3 RU 10 on Windows 2008 R2 1 x Exchange 2013 CU 10 on Windows 2012 R2 I can connect with Outlook on a Windows 7 client with Outlook 2013 I can connect with Outlook on Windows 8 client with Outlook 2013 I can not connect with Outlook on Windows 10 client with Outlook 2013 Get the error “The connection to microsoft exchange is unavailable. Outlook must be online or connected exchange” during the startup wizard for the Windows 10 client. I have stopped all firewalls on client and servers but no change. Do I have to set up any additional configuration in AD/Exchange to connect with Windows 10 clients? Thanks for any suggestions/comments. /M