I download VHD from Azure VM(ubuntu 16.04.2 LTS), and run it on Hyper-v, I can use my original account to login it:
Could you please tell me which account are you use to login? By default, we can't use root to login it.
By the way, several mouths ago, I can't use original account to login this VM on Hyper-v. If your VM create in that time, we should use OS file to to reset the password, or we create a new Ubuntu and download it again.