In a brand new Windows Server 2012 R2 VM (provided by Dell), I downloaded all of the available updates from Windows Update and started the installation. After a long period of time, the VM rebooted and I got the following message:
We couldn't complete the updates
Don't turn off your computer
There is at least one Windows Update that expects Bitlocker to be installed for Gen 2 VMs. You don't need to encrypt anything but the feature needs to be installed. On my system it was Security Update KB2920189 that seemed to cause the issue.
You might be able to install BitLocker by booting the VM into safemode. However, there is a better way. On the Hyper-V host, you can use Server Manager to add the feature to the VM while it is turned off.
To see the details with beautiful screenshots, check out this link: