Zend certified PHP/Magento developer

tricky user profile issue on a Windows Server 2012 R2 machine

Need some help with a tricky user profile issue on a Windows Server 2012 R2 machine acting as a CAS server.

Here’s the scenario:

I’m using Hyper-V manager on another Windows Server 2012 R2 to connect to the CAS server VM.
When I try to log in, I get a frustrating error message: “The User Profile Service failed the sign-in. User profile cannot be loaded.”
This is preventing me from accessing the CAS server! Any ideas on how to fix this issue?