Hi, Linda Taylor here, Senior Escalation Engineer from the Directory Services team in the UK.
I have been working on this issue which seems to be affecting many of you globally on windows 8.1, 2012 R2 and windows 10, so I thought it would be a good idea to explain the issue and workarounds while we continue to work on a proper fix here.
The symptoms are such that after a password change, logon hangs forever on the welcome screen:
The underlying issue is a deadlock between several components including DPAPI and the redirector.
For full details or the issue, workarounds and related fixes check out my post on the ASKPFEPLAT blog here http://blogs.technet.com/b/askpfeplat/archive/2016/01/11/does-your-win-8-1-2012-r2-win10-logon-hang-after-a-password-change.aspx
I hope this helps,