I was going to put this in its own thread, but I guess I'll just toss it in here - Win 10 Outlook & Exchange not playing nice.
Okay, so for reasons that aren't important I needed to setup Outlook to connect to a users (Microsoft Hosted) Exchange mailbox. Being that for fun I though I'd try doing it in the Windows 10 VM ... I started with Outlook 2007 to see if/how compatible it might be. The auto configure ran, found the server, found the account, and then went into a loop prompting me for the credentials, which while correct were not being accepted.
Being that auto configure was new in/for 2007, I then upgraded it to Outlook 2010, and that too exhibited the same credential prompting ill behavior. I didn't have time to try Office 2013, so that option got skipped. I had to use a copy of 2010 in Windows 7 to get the job done.
One thing I did notice during this is when I attempted to go the hosted Exchange login page (portal.microsoftonline.com) in IE, I got redirected to some other (apparently new) MS service page I've never heard of. So I'm wondering if that redirection - which appears to be buried in the bowels of the OS - is what was killing the Outlook auto config connection. Neither the VM host machine, or any of the other VM's got bounced to this other (odd service that I can't remember the name of - Sorry) page ... And it was a vanilla install of the latest Windows 10 CTP.