How to link Windows 10 domain user account to Microsoft account?

As it turns out, the method I had to use (though I don't know if this is the only way going forward) is to set up Cortana. Doing so made me link my account and choose my sync settings.

I was tipped off by a post at the following url: http://forums.windowscentral.com/windows-10-technical-preview/359824-connecting-domain-account-microsoft-account.html

All I had to do was select the search bar in the taskbar, and follow the steps to opt-in to using Cortana. I was eventually asked to sync to a Microsoft account.

This problem arises from the circumstance where you have a domain-joined Windows 10 computer running Windows version 1703 aka the Creator's Update.

The answer is because Microsoft chose to remove this functionality. Of course, without informing users, without updating the messages on their Sync your settings screen, without updating online documentation, and without informing their own support desk. If you are an insider, info about this can be found on here.

By the way there are a couple of workarounds:

1. if you can, perform a clean install of Microsoft Windows 10 build 1607, set up your sync settings, then upgrade. Testing shows this feature successfully remains if you have it in place before upgrading to the Creator's Update.

2. if you have a computer that still has this sync enabled,

   • open RegEdit, navigate to HKEY_USERS\.DEFAULT\Software\Microsoft\IdentityCRL\StoredIdentities. You should find your Microsoft account listed as an entry under this, and under that, the Security Identifier - or SID - for your domain-joined account. Export the entire Microsoft account registry branch under StoredIdentities.
   • Move this to your new computer, then import into your registry. Double-check your SID is correct, though provided you've signed in with the same Active Directory account, then it should be. You can confirm by browsing further down the registry under HKEY_USERS and noting the SID there.
   • Open Settings/Accounts/Sync your Settings again and this time it is all open, enabled and manageable.

You will not be able to sync passwords until you verify your identity on the new computer but that's a trivial exercise.